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4L80E behind 6bt

27K views 52 replies 7 participants last post by  MaxPF 
#1 ·
I'm looking to install a transmission behind my 6bt (12v VE pump). I currently have the Tf727 that came with it.

My question is, how reliable is the 4l80e behind the Cummins? I'm aware that the swap should be straight forward, Summit Racing have all the necessary parts needed to complete the swap.

Should I rebuild the Tf727 or should I invest in the 4l80e swap?

Where I'm from, Dodge transmissions are virtually nonexistent (47rh/47re/48re), otherwise this would have been the preferred choice.

The truck will be used mainly for highway driving and I'm only looking to make 400-500 hp out of it. No towing or hard launching.

Any input or feedback is highly appreciated.
 
#2 ·
For you projected power level I'd guess the 4L80e would fail. Might not be the HP that would kill it but the incredible amount of torque which will be in the neighborhood of 1000 lb ft. You say it now has a TF727. Does the truck have the 3.07 gears in the differential? Most of the 4L80e's we've seen used were with 4bt's with far less power than you plan. Even the TF727 would need a serious rebuild plus a billet flex plate and very good torque converter. Just curious, if you're only doing basic highway driving why do you need 400-500 HP?
 
#3 ·
Hi Char1355,

Thanks for the reply,

The engine and tranny came out of an 89 Dodge airplane tug truck. The differential gears are 7.16, I've replaced the whole diff for a GM 14 bolt (4.10) for better drivability.

Being that it isn't street legal, I only drove the tug truck around the block. The truck wants to go and it's really torquey but it's clearly limited by the diff gears and extra weight in the back. (the speed is limited to 55 mph).

The engine is going into a 77 Dodge Truck W200. It's already been rebuilt (stock parts only for now) and it's already mocked up into place, both differentials have been swapped to a Dana 60 front and the 14 bolt rear.

The required hp number is for the occasional street launch here and there, not serious drag racing or making passes constantly.

The plan is to break-in the engine gradually and make sure everything is seated properly. After about 2k miles or slightly more, I'll do the upgrades.

Maybe I should have cleared it up better in the original post.. Would it be better to go with the TF727 for now (especially for highway driving) and replace it later with a rebuilt Dodge tranny (I'll have to import it and it would cost a lot just for shipping, let alone the transmission), or should I buy and upgrade the 4l80e from now (i.e would it handle the extra power later)?

Thanks again
 
#4 ·
Being out of the country does have it's limits. Since you have 4.10 gears you definitely need something with an OD gear for any decent highway speed unless you have huge tires. Adapting a 4L80e will be expensive and I don't think it will survive your power. The 14 bolt is going to be stressed with a 500 HP diesel. When you hit the accelerator pedal the rear tires are going up in smoke instantly. Better plan on some strong U joints and HD drive shafts. Have you possibly thought about an Allison. The 1000, 2000, and 3000 series came behind a 6bt. Of course, none of those are cheap or small. An Allison 3060 is rated at 950 lb ft input torque with options up to 1600 lb ft and came in medium duty trucks. That was a 6 speed with dual OD gears. Of course doing 4x4 with that would be an issue. The 1000/2000 came in 4x4 models. Late model GM diesel pickups use the 1000.
 
#5 ·
Ideally I would go with a fully rebuilt 47/48RE. I wouldn't mind paying around $4k for an ATS unit for example that only requires me to install it, but shipping is ridiculously expensive.

I'll look into the Allison 3060. I might find one for relatively cheap in my local junkyard. Medium sized diesel trucks aren't really popular here, the preferred diesel trucks here are mostly the smaller 4 cylinder Isuzu/Hyundai/Toyota/Tata ones. So I might get lucky just like I got lucky with the tug truck?

Could you point me to specific things I should be looking for? Specific serial numbers on transmission tags maybe? And what should I look to buy/pick up if I happened to come across one (ECU, flex plate.. etc)?

Really appreciate your valuable input Charles
 
#6 ·
Well, a 3060 Allison might be a tall order. As I mentioned it doesn't have a 4x4 case so you'd need a divorced transfer case. Second it is one big sucker. Weighs around 600 lbs dry and holds 29 qts of fluid. Application was medium duty trucks with various engines, some buses, and motorhomes. Requires an SAE2 transmission mount on the engine which is common for a Cummins. Here's a link to its spec sheet. https://jexler.s3.amazonaws.com/safari/data/Allison 3060 specs.pdf Below is a photo of one and the ID plate. We've had a few guys use that transmission but mostly in 1-1/2 ton trucks or RV's. The Allison 1000 and 2000 series are rated for up to 300 HP and 780 lb ft torque and maybe a bit more. They have changed some over the years but 500 HP might be a bit much on one of those. The 1000 is used behind the Chevy Duramax diesel in their pickups and has a 4x4 option. The 2000 series is just a more heavy duty version of the 1000. Physically the same size. They came in 5 and 6 speed models. Must remember these things are computer controlled. Have to be careful when looking in the salvage yard. Allison made a lot of lighter duty automatics that were used behind Cummins diesels like the AT545. Found a lot in school buses and delivery vans. Has no OD gear and very low power rating.
 

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#7 ·
Holy cow!! 600 lbs dry and 29 qts of fluid!! That has to weigh more than the engine. It's no bueno in that case.

I'll try to find a 1000 or a 2000 series Allison. It'll be a lot harder to find a GM Duramax here, but I'll look into the junked firetrucks/ambulances area.

Thanks for the tips, I'll read more in the sticky thread about Allisons. If I did find one, I'll try to get everything that's transmission related off of the donor.
 
#8 ·
No, the 3060 is about half the weight of a 6bt. The 6bt weighs 1100 lbs. Nothing light about a Cummins diesel or at least the older ones. That transmission will be serious overkill for most any swap. The Allison 1000 and 2000 came in both 5 and 6 speed. Depends on which computer program they got. Those typically have the SAE3 bellhousing in commercial applications. You might have to use an outboard transmission control module. Often the Cummins had the transmission computer tied to the engine computer. That stand alone controller tends to be a bit expensive at around $1600. That's for a 6 speed. Not sure about a 5 speed. Should you find a 1000 or 2000 that is 2wd it can be converted to 4x4 by changing the rear assembly. Those parts aren't cheap either. Then you'd need a transfer case. Option would be stay with a 2wd transmission and do a divorced transfer case. By the way, what country are you in?
 
#9 · (Edited)
My mistake about the weight,
I looked into the prices of standalone controllers before, they're definitely not cheap..
Is there a clear way of telling which bellhousing I'm looking at (without having to teardown the transmission)?
I'm in Saudi Arabia btw.
The reason diesel trucks aren't popular here for the average consumer here is the bad reputation they have (think old GM V8 diesels, non turbo), and gas is cheap. Unfortunately people still think diesel trucks are low on power and problematic.
The ones we get are commercial and industrial grade engines. Lots of 6ct Cummins (8.3 ISC for example) and other CAT engines (mostly for agriculture use).
The only reason I have a 6bt Cummins truck is because it's an ex military truck that was used by the US Air force in the Gulf War.
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#12 ·
Are there any military vehicles in the salvage yards there. If so, many of those might have Cummins diesels and Allison transmissions. The 1000/2000 series wouldn't be in any super sized trucks. Those would likely be in the 3000 series if they weren't manual. Never hurts to scrounge around the junk yards. Any US military base close by? Maybe you could talk to one of the mechanics in the motor pool and they might give you some leads. The main issue with an Allison is if it needs rebuilding that can be expensive. Of course rebuilt other automatic transmissions aren't exactly cheap either.
 
#13 ·
I'm going to have to counter some of char's information. First off, a 500HP diesel isn't going to stress a 14b. 14bolts have a saddle bearing on the pinion like a 9" Ford, and this makes the R&P much stronger than an equal size overhung pinion unit like the D70. In fact, the "weak" link on a 14b, which isn't weak by any stretch, are the axle shafts, and those same shafts are used in the 11-½" AAM axle. The 11-½" unit, which is used on 3/4 and 1 ton GM and Dodge diesel pickups, does NOT have a saddle bearing like the 14b. It is a conventional overhung pinion design, and neither the pinion nor the pinion shaft is any larger than the pinion and pinion shaft on the 14b. I could go into a dissertation on why larger R&P is needed for an axle rated at higher GCWR, which has to do with how much tooth contact area the load is applied to on a continuous basis to keep localized temps down for durability, but suffice it to say you won't break the R&P on a 14b and if you break a 14b shaft then you would break an identical 11-½" AAM shaft. As long as you don't plan on towing over 18k GCW or so, the 14b will be perfectly fine. Note that 18k is very conservative, as second gen Dodge guys have routinely towed mid-high 20k range with the weaker D70 without any R&P issues. While I don't mind putting more torque through an axle than it is rated for, I like to stay within the GCWR limits to get essentially indefinite life out of the axle. Also, the 14b and 11-½" AAM use the same pinion yoke, and the 11-½" axles came with 1480 u-joints, so a 1480 yoke can be installed on the 14b if you find you're eating up 1410s.

Forget a 3000 series Allison. These are just too large for a pickup, and the smallest flywheel housing they accommodate is SAE #2 which is also too large for most pickups, unless you don't mind breaking out the Sawzall on the firewall. In stock form the 1000, 2000, and 2400 series have pretty modest ratings, but GM has increased the ratings on the 1000 series to 445HP, 910lb-ft of input torque, and a GCWR of 31,300lbs. Contrary to popular belief, while the 2000 and 2400 series have higher ratings, they all are identical internally except for gear ratios and presence or absence of a park pawl in some models. The park pawl has a weight limit, so it reduces the GCWR of the trans relative to the units without the park pawl. The transmissions with the deeper 3.54 gear sets reduce upstream load, so those transmissions tend to carry higher GCWRs vs the transmissions with 3.10 gear sets. Other factors are determined by TCM programming, which is in turn based on vocational use. Any Allison can be built to handle 500HP/1000lb-ft or so, but its really best to have working torque management. Allison 1000/2000/2400s typically use SAE #3 flywheel housings in non-GM pickup applications. The GM pickup 1000's use the standard GM corporate (aka SBC/BBC) flywheel housing. There were also SAE #2 housings available for these series, but they seemed to be rarely used since the converters on these smaller Allisons fit in the smaller #3 housings. If you are DIY rebuilding an Allison and no hard parts are needed, then the cost is comparable to a 4L80E. The biggest single expense is a good triple disk torque converter. Ally's usually don't need hard parts because they are robust internally. If they do, the price really depends on whether you can locate good used parts or have to spend the money for new. FWIW, Allison wholesaler outlets are MUCH cheaper than GM dealerships when it comes to hard parts. Clutches and steels are usually obtained in aftermarket kits that come with other mods.

500 diesel HP in a 4L80E (4L85E really) is problematic because such an engine will make around 1000lb-ft or more. There are shafts available that can handle that much power, but the main limitation is the OD roller clutch. Especially the later transmissions that uses the clutches with smaller diameter rollers. The torque will eventually blow that roller clutch apart. It's also difficult to get the OD clutches to hold that much torque. It's doable, but like I said even if you get that done it will just blow the OD roller clutch apart anyway. The most tq the 4L85E handled in stock form was 520lb-ft-lbs. That was when the trans was used behind a detuned Duramax in the Express vans. The only reason it was used was because the Allison would not fit on that van chassis.

It's much easier to build a 47RH/47RE/48RE to hold the power because they came behind the Cummins as the stock trans, and the aftermarket has made huge strides to get these transmissions to survive at high power levels. If you're fine with a 4 speed automatic. I'd stick with one of those, built for your power level.
 
#50 ·
I'm going to have to counter some of char's information. First off, a 500HP diesel isn't going to stress a 14b. 14bolts have a saddle bearing on the pinion like a 9" Ford, and this makes the R&P much stronger than an equal size overhung pinion unit like the D70. In fact, the "weak" link on a 14b, which isn't weak by any stretch, are the axle shafts, and those same shafts are used in the 11-½" AAM axle. The 11-½" unit, which is used on 3/4 and 1 ton GM and Dodge diesel pickups, does NOT have a saddle bearing like the 14b. It is a conventional overhung pinion design, and neither the pinion nor the pinion shaft is any larger than the pinion and pinion shaft on the 14b. I could go into a dissertation on why larger R&P is needed for an axle rated at higher GCWR, which has to do with how much tooth contact area the load is applied to on a continuous basis to keep localized temps down for durability, but suffice it to say you won't break the R&P on a 14b and if you break a 14b shaft then you would break an identical 11-½" AAM shaft. As long as you don't plan on towing over 18k GCW or so, the 14b will be perfectly fine. Note that 18k is very conservative, as second gen Dodge guys have routinely towed mid-high 20k range with the weaker D70 without any R&P issues. While I don't mind putting more torque through an axle than it is rated for, I like to stay within the GCWR limits to get essentially indefinite life out of the axle. Also, the 14b and 11-½" AAM use the same pinion yoke, and the 11-½" axles came with 1480 u-joints, so a 1480 yoke can be installed on the 14b if you find you're eating up 1410s.

Forget a 3000 series Allison. These are just too large for a pickup, and the smallest flywheel housing they accommodate is SAE #2 which is also too large for most pickups, unless you don't mind breaking out the Sawzall on the firewall. In stock form the 1000, 2000, and 2400 series have pretty modest ratings, but GM has increased the ratings on the 1000 series to 445HP, 910lb-ft of input torque, and a GCWR of 31,300lbs. Contrary to popular belief, while the 2000 and 2400 series have higher ratings, they all are identical internally except for gear ratios and presence or absence of a park pawl in some models. The park pawl has a weight limit, so it reduces the GCWR of the trans relative to the units without the park pawl. The transmissions with the deeper 3.54 gear sets reduce upstream load, so those transmissions tend to carry higher GCWRs vs the transmissions with 3.10 gear sets. Other factors are determined by TCM programming, which is in turn based on vocational use. Any Allison can be built to handle 500HP/1000lb-ft or so, but its really best to have working torque management. Allison 1000/2000/2400s typically use SAE #3 flywheel housings in non-GM pickup applications. The GM pickup 1000's use the standard GM corporate (aka SBC/BBC) flywheel housing. There were also SAE #2 housings available for these series, but they seemed to be rarely used since the converters on these smaller Allisons fit in the smaller #3 housings. If you are DIY rebuilding an Allison and no hard parts are needed, then the cost is comparable to a 4L80E. The biggest single expense is a good triple disk torque converter. Ally's usually don't need hard parts because they are robust internally. If they do, the price really depends on whether you can locate good used parts or have to spend the money for new. FWIW, Allison wholesaler outlets are MUCH cheaper than GM dealerships when it comes to hard parts. Clutches and steels are usually obtained in aftermarket kits that come with other mods.

500 diesel HP in a 4L80E (4L85E really) is problematic because such an engine will make around 1000lb-ft or more. There are shafts available that can handle that much power, but the main limitation is the OD roller clutch. Especially the later transmissions that uses the clutches with smaller diameter rollers. The torque will eventually blow that roller clutch apart. It's also difficult to get the OD clutches to hold that much torque. It's doable, but like I said even if you get that done it will just blow the OD roller clutch apart anyway. The most tq the 4L85E handled in stock form was 520lb-ft-lbs. That was when the trans was used behind a detuned Duramax in the Express vans. The only reason it was used was because the Allison would not fit on that van chassis.

It's much easier to build a 47RH/47RE/48RE to hold the power because they came behind the Cummins as the stock trans, and the aftermarket has made huge strides to get these transmissions to survive at high power levels. If you're fine with a 4 speed automatic. I'd stick with one of those, built for your power level.
SAE sounds like Oil to me.. as some old guy trying to peice together the info on here.. It appears my cummins has an SAE #3 bellhousing ( I also happen to have a 5.9 24 valve to NV adapter..) want to marry that to a 700r4 that was rebuilt for towing with a 6.2L.. the 6.2l diesel leaks oil like a pig so I'd like to find an adapter to go from the 700r4 to a SAE # 3.. ( with a big heavy flywheel outs some industrial rig... ) if you could tell me where to go, I'd appreciate the assistance....Thanks

Some Old Guy
 
#14 ·
Max, I didn't mean that the 14b would fail, but dumping around 1000 lb ft of torque into it will stress it. I'd most definitely agree the 3060 is way overkill in a pickup. Even a 1000/2000 will probably require some transmission tunnel mods. They are not small transmissions. Not all Allisons have a high torque rating like the latest Duramax. I believe the base transmissions only have 620 lb ft input torque rating. On the power plan, a VE pump engine has limits. Not sure if you can get one to 500 HP but that may be possible. 450 HP is probably a better target. 300 HP on a 4bt is pretty much the limit. Might be able to do 450 HP on a single turbo but twins would be nicer. Main issue with this build is going to be logistics. He's in a foreign country the other side of the world where diesel stuff is kind of rare and a long way from any parts store.
 
#15 ·
Re the 14b, I understand what you're saying. My point is that it isn't being any more stressed than the larger ring gear 11-½" AAM axle would be. Now, if towing very high GCW with that power the bigger ring gear has the advantage that the load is spread out over more gear area, so overall wear will be less per mile, but again it isn't a huge factor. FWIW, Ford used their 10.5" Sterling axle, which have a weaker and less robust ring and pinion vs the GM 10.5" 14b, in their F-250 and F-350 Super Duty's, including those with diesels making 700-900lb-ft of torque. That was their ONLY axle for SRW trucks until 2017, when the Dana 275 (for F-250's with HD tow package and SRW F-350's) and Dana 300 (DRW F-350's) were brought in to cope with the increasing GCW ratings games that the big three are playing. Because of those facts I have zero concern about the 10.5" Corporate 14bff being "stressed" unless a ridiculous amount of weight is being towed. More weight than would be safe to tow with a SRW truck.

A standard spec-sheet Allison 1000 series is rated for up to 340HP, 575lb-ft maximum input torque, 660lb-ft max input torque with SEM torque limiting, 950lb-ft maximum turbine torque, and up to 30,000lbs GCWR. The 2500 has the same HP and tq ratings as the 1000 series but is rated for a maximum 33,000GCWR. The GM versions of these transmissions that are rated for over 450HP, over 900lb-ft of tq, and 31,300GCWR use the same hard parts as the standard lower-rated 1000's. The three differences are A) GM-specific torque converter (Pre-2010 GM Ally's used a standard Allison converter part number), B) GM-specific clutches, and C) GM-specific calibrations in both the TCM and ECM. The latter is the main reason the trans can handle so much extra torque. The weak period in any automatic is during shifts when energy has to be dissipated in the clutches and the clutches have to be able to overcome the applied torque and actually lock up. Once the clutches are locked they can handle much more torque without breaking free. The shift and ECM calibration is pretty basic; defuel the engine to reduce torque to the point where the clutches can actually lock during the shift, then restore the pre-shift fueling. This way, the trans clutches and TC clutch only need to handle the static 910lb-ft of torque once applied and locked up, not while slipping and trying to lock. With aftermarket goodies Allisons can handle in excess of 1500lb-ft, although once you get into the 1000+lb-ft range AND you have the shift timing and defuel reduced (i.e. for racing or sled pulling) you are going to need aftermarket input, intermediate, and output shafts made of higher strength steels. Duramax guys who race and pull and are running over 500-550HP with aggressive tunes start breaking shafts at that point. OTOH, all other light truck transmissions need high zoot billet parts at less HP and tq than the Ally, so it isn't like the trans is weak by comparison. The hardest part of running an Ally at high power and aggressive tuning is avoiding the 3-4 shift tie-up, which is what tends to break things. You can avoid it by slowing the shift speed considerably and defueling more aggressively, but then you won't be competitive in racing or pulling. This is why hard core Dmax competition guys were swapping to 47RH-48RE hybrids, and now more and more are running highly customized and expensive TH400's with lockup converters and billet everything. Those are great for racing, but lack of OD makes them less than useful on the street.

I agree with your logistics statement. That is always a problem for guys in many other countries, unfortunately.
 
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#16 ·
Char1355, MaxPF,

Sorry it took me a while to reply. I didn't have the time to do so for the past week.
Really helpful information in your replies.
I contacted a few junkyards and one of them says they think they have the transmission I'm looking for (the Allison 1000 or 2000), he's still not sure as he didn't understand where to look for on the transmission to take a pic of the tag.
He mentioned that it's from a Freightliner Truck (he doesn't know the model of the truck but from his description, I found out it's an M2 106 model and after a lot of digging online, it's true they did come with the Allison behind their engines. However, it could also be an Eaton Fuller 6 speed Auto. Here's a link Freightliner M2 106 Specifications | Freightliner Trucks
I'll try my best to go check it out this weekend or the following one. This junkyard is about an hour and half drive (one way).
I'll take pics of the transmission and the ID tags and I'll post them here as soon as I can.
Thanks again Charl1355 and MaxPF for the valuable information and discussion, I'm sure I'll be asking more questions in the near future.
 
#19 ·
Char1355, MaxPF,

Sorry it took me a while to reply. I didn't have the time to do so for the past week.
Really helpful information in your replies.
I contacted a few junkyards and one of them says they think they have the transmission I'm looking for (the Allison 1000 or 2000), he's still not sure as he didn't understand where to look for on the transmission to take a pic of the tag.
He mentioned that it's from a Freightliner Truck (he doesn't know the model of the truck but from his description, I found out it's an M2 106 model and after a lot of digging online, it's true they did come with the Allison behind their engines. However, it could also be an Eaton Fuller 6 speed Auto. Here's a link Freightliner M2 106 Specifications | Freightliner Trucks
I'll try my best to go check it out this weekend or the following one. This junkyard is about an hour and half drive (one way).
I'll take pics of the transmission and the ID tags and I'll post them here as soon as I can.
Thanks again Charl1355 and MaxPF for the valuable information and discussion, I'm sure I'll be asking more questions in the near future.
You definitely don't want the Eaton AutoShift. They are not a true automatic. They are an automated manual transmission. In essence, they are an FSO 6 speed with no synchros, and electric servoc operating the clutch and shifter. They require very specific calibration in the ECM for defuel and shift speed synchronization. Compared to a conventional automatic like the Allison, automated manuals are rather clunky shifting, not to mention slow shifting. I wouldn't want one in a big truck, let alone a pickup.

If it's an Allison it could be either a 1000 or 2000, or a 2400. All of these big trucks use 2WD automatics, and generally they have no park pawl, so they are less than ideal for a pickup. IIRC, all the transmissions are drilled for the pawl pin, so adding a pawl wouldn't be a big show stopper IF that is the case. Another issue is gearing; the trans could either have the 3.10 gearset or the 3.54 gearset. The former is better suited for a pickup, but either will work with the right diff gearing.
 
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#17 ·
Like you, no telling exactly which transmission is in that truck until you look. None of those automatics are physically small, but the 1000/2000 are probably the least. We know the 3000 Allison is a big monster. The Eaton could be one of 2 models, FO-6406A-ASW or FO-8406A-ASW. Those definitely aren't small either. May be even bigger than an Allison 3000.
 
#18 ·
Knowing my luck, I'm sure it's probably the 3000 or even the Eaton. Only one way to find out for sure though. :cry:

The trans tunnel had already been cut, we mocked up the 5.9 and Tf727 in place of the NP 435 that came with it (it had the LA 318). So, cutting up the trans tunnel a bit more shouldn't be a problem now.
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#20 ·
Max. according to Allison, the 1000, 2200, 2350, and 2550 came with a parking pawl (P on shifter). The 2100, 2300, and 2500 models use a mechanical park brake (PB on shifter). And they did make models that don't have either position on the shifter. The shifter designation would tell you if the park pawl is present. Here's a link to Allison's manual. https://www.carolinathomas.com/wp-content/uploads/2014/05/1000-2000-operators-manual.pdf
 
#21 ·
Yeah, I know the model differences. I was just pointing out general differences for 77 to look for. Here is a brochure of the CURRENT vocational models being made by Allison. This list is not complete, as it doesn't include previous, now-discontinued models (i.e. the 5 speed versions of the 1000/2000 series):

https://allisontransmission.com/doc...vocational-model-guide.pdf?sfvrsn=1bf83f1d_19

It's interesting the wide variation of GVWR/GCWR available in that Freightliner M2 106 chassis. As an Allison 1000 series is an option, that means the truck comes in at a GVW of 19,500 and GCW or 30,000. They advertise the Allison 3000 series as an option, most likely only with the Cummins L9, although possibly with the Detroit DD8 as well, and that would allow the M2's maximum 66,000lb GVW configuration. So, until he looks at that truck there is no telling what it may have for a transmission.
 
#22 ·
Max,

Just today I completed reading the complete Allison info thread and was wondering about a few things. Really helpful info over there, your contribution is amazing and the other members too.

I'll be going to the junkyard this Saturday and wanted to make sure I'm not missing anything..

I'll be looking out for the Allison that came in the 8100 GM pickup trucks first before checking out the Freightliner I mentioned before. We did get a lot of 8100 engines here, but unfortunately most of them were in the Suburbans (I'm sure the Allison only came in the pickup trucks, but I'll look in the SUVs anyway since I'll be there).

If I happened to find one, what should I get besides the transmission? I'll definitely try to get the harnesses and TCM, am I missing something else?

If I didn't find the 8100 Allisons, and went for the Freightliner (or any other similar truck), should I get the harness and TCM too?

I was looking more into other potential donors for the transmission and I think I might run into the Chevy Kodiak / GMC Topkick.. I've read they came with the Allison too (1000 and 2000 series). Should this be a good place to pick one up from or should I not bother since they have the Duramax engines and therefore the controller for those engines? I'm thinking of buying the standalone controller from transmissiontuner. com since a lot of members had good things to say about Jason and his services and expertise.

Another thing, Is the Allison 1000, 2000, 2400 series the same in terms of aftermarket support? For example, if I bought a 2400 series and wanted to upgrade the internals later with aftermarket parts, would parts be swappable or would they need to be custom made?

I know it's difficult to list parts because every swap is different.. My engine is the first gen Cummins (12v, non intercooled, VE pump).. I'll add an intercooler and do a P Pump swap (but the pump swap will be a bit further down the road). I'll run it with the VE pump for a while.

Thanks in advance, you've really changed my mind about going for the Allison rather than invest in something inferior.

Thanks again for your patience with my rookie questions
 
#23 ·
Max,

Just today I completed reading the complete Allison info thread and was wondering about a few things. Really helpful info over there, your contribution is amazing and the other members too.

I'll be going to the junkyard this Saturday and wanted to make sure I'm not missing anything..

I'll be looking out for the Allison that came in the 8100 GM pickup trucks first before checking out the Freightliner I mentioned before. We did get a lot of 8100 engines here, but unfortunately most of them were in the Suburbans (I'm sure the Allison only came in the pickup trucks, but I'll look in the SUVs anyway since I'll be there).
The Suburbans equipped with the 8.1L used the 4L85E, not the Allison. The 8.1/Allison combination was only available in the 2001-2006 Silverado and Sierra 2500HD and 3500HD pickups and a few medium duty truck models (i.e. Kodiak and Top Kick). You will likely have more luck finding one out of a Duramax truck, but again they were only used in the HD pickups and MD trucks. The Express vans with the Duramax used a 4L85E behind a derated engine. If you want to run the 8.1L calibration you will need a 2009-earlier Allison and a 2006 TCM. Of course, the 2005 and earlier will be 5 speeds while the 2006-up will be 6 speeds.

If I happened to find one, what should I get besides the transmission? I'll definitely try to get the harnesses and TCM, am I missing something else?

If I didn't find the 8100 Allisons, and went for the Freightliner (or any other similar truck), should I get the harness and TCM too?
ALWAYS get the wiring harness and TCM if available.

I was looking more into other potential donors for the transmission and I think I might run into the Chevy Kodiak / GMC Topkick.. I've read they came with the Allison too (1000 and 2000 series). Should this be a good place to pick one up from or should I not bother since they have the Duramax engines and therefore the controller for those engines?
The TCM can be reflashed to an 8.1L calibration as long as it is a 2006-earlier unit.

I'm thinking of buying the standalone controller from transmissiontuner. com since a lot of members had good things to say about Jason and his services and expertise.
I don't know anything about his stuff since I roll my own (and have something in the works that will be far ahead of the typical 8.1 or MD swaps). Unless you have the expertise to do so, you will have to use his unit or have someone else configure the harness and TCM for your needs. Most people find this kind of thing to be very daunting, so buying a ready-to-go controller setup is often the best option.

Another thing, Is the Allison 1000, 2000, 2400 series the same in terms of aftermarket support? For example, if I bought a 2400 series and wanted to upgrade the internals later with aftermarket parts, would parts be swappable or would they need to be custom made?
The 1000 and 2000 series have the exact same hard parts (except for the rear planetary assembly and sun gear on wide ratio models) and clutches. There are differences between the 2005 and earlier 5 speeds and the 2006-2009 6 speeds, however. The gearsets of the 2001-2005 models have a shallower helix angle vs the 2006-up 6 speeds. This was supposedly done for noise; there is no strength advantage to either one. You cannot mix and match parts from the two geartrains, but you can swap the entire gearset from one to the other since the cases are identical. 5 speeds also have a different input drum assembly vs the 6 speeds. The 5 speed drum's pistons apply the clutches off center, vs the 6 speeds that apply on center (which is better for even clutch wear). The 5 speeds also have a slightly more complex apply piston configuration with an extra "balance" piston, whereas the 6 speed simplified the arrangement by deleting the balance piston. Although the drums are different, they use identical input shafts. From 2010-onward. the GM-manufactured Allison LCT1000 used in GM's pickups may have diverged from the Allison-manufactured 1000/2000 series. GM went to a full variable line pressure valve body and pump, and they changed the input, intermediate, and 4WD output shafts. I know the 4WD output shaft was changed to a larger spline count (34 spline, IIRC). I'm not sure about the input and intermediate shafts as they look identical in pics. Larger diameter and more splines, perhaps? It didn't seem so in the pics, but then again it was hard to tell.

Another big unknown on the 2010-up GM Allisons is whether the Allison-made SAE #3 bellhousing will work on them, given possible changes made for variable line pressure operation. I am currently researching all of these items and I will fill in the blanks in this thread when I find out.

I know it's difficult to list parts because every swap is different.. My engine is the first gen Cummins (12v, non intercooled, VE pump).. I'll add an intercooler and do a P Pump swap (but the pump swap will be a bit further down the road). I'll run it with the VE pump for a while.
Most guys end up keeping the VE pump. The only real good reason to do a P-pump swap is if you want to make big power, and if that is the case you are going to need big money to keep the trans alive. I always tell guys to be realistic with their power goals. My engine is around 250HP 750lb-ft and it hauls butt quite nicely. It's amazing how gobs of low end torque can get a vehicle moving, even if the actual HP number is fairly modest.

Thanks in advance, you've really changed my mind about going for the Allison rather than invest in something inferior.

Thanks again for your patience with my rookie questions
No problem. Good luck with your search. (y)
 
#24 ·
Max, I believe he's been saying he wants power in the 400-500 HP range. As we both know, that's a hell of lot of power and it will produce some extreme torque that can have destructive effects. Unless the program is modified, the Allison 1000 and 2000 will have a hard life at that power level. Guys running the Duramax with the power turned up have had problems with the 1000 needing some upgrades. Will be some serious questions on U joints and differentials at that power level.
 
#27 ·
I'm aware it's a lot of power at that level (especially the torque). The truck will be mainly driven on the streets and the occasional launch here and there, but it won't be seeing any racing.
The 500 HP is just a number, it's not something I'm obsessed about achieving for bragging rights, it's just a basic target.
Having never driven diesel trucks before (diesel anything in fact), I'm not sure I'll look for more power over the stock (+ basic bolt on mods). I just need to drive it properly first before deciding to look for more power.
 
#25 ·
Most Cummins engines have a roughly 1:2 HP/tq ratio. So, a 400HP engine makes around 800lb-ft, and at 500HP you're around 1000lb-ft. Some get to a 1:2.3 or even 1:2.4 or 1:2.5 ratio, so the torque on a 400HP build could be as high as 1000lb-ft, and as high as 1250lb-ft from a 500HP build. My engine is about 1:3, which is uncommon for a Cummins and more typical for a Caterpillar, but it's not the engine itself that makes the difference but rather the fueling curve and having enough air available. As it is, I'm hazing really good at that torque level. If I were tuned for clean exhaust at full throttle torque peak I would be back into that 1:2.4 or 1:2.5 arena that is more typical for lower HP Cummins engines. In other words, I'm cheating :)

So, yeah, he will need upgrades. Definitely gonna need to run the full Alto packs, the Transgo kit, and a solid dual or even a triple disk converter. In other words, a full Suncoast-type build. The Allison has pretty beefy shafts compared to other transmissions like the 47/48RE or 4L80E, so they should be OK as long as he's not sled pulling or doing full boost launches. The biggest issue is trying to keep shift energy down by speeding up the shifts. This inevitably leads to 3-4 shift tie-ups which can tear up the C2 clutch hub and P2 planetary splines. This ends up being one of the biggest limitations at high HP levels. The solution on a Duramax is simple: increase defuel during shifts. The clutches can hold a ton of torque once locked, and shafts and other parts can tolerate a lot of torque if not shock loaded all the time. With aggressive defueling, shifts can be slowed considerably (were talking tens or hundreds of milliseconds) while putting less energy into the clutches and not stressing the hard parts. Drag racers and sled pullers don't want to do this because too much defuel drops boost and increases ET's in drag racing and can cause you to lose the pull in sled pulling. For street heroes it's much less of a problem. Unfortunately, 12V Cummins, being mechanically controlled, have no way to defuel. I have a solution for being able to electronically defuel a mechanically injected engine, but it's still under development. For now, he will simply need to limit the HP and torque to levels that won't burn clutches or tear up splines. At those levels he also won't need t worry about upgraded shafts.

He also hasn't mentioned whether he has a driver drop or pass. drop front diff. This matters, because there are more HD options available for driver drop cases.

The diffs will be OK. He should run at least 1410 u-joints, and I would recommend 1480 on the rear. As I mentioned before, he won't have any problems with the 14b rear. The old W200 chassis isn't going to be able to tow or haul nearly as much weight as a modern 3/4 ton chassis, so the 14b will be fine even if he wants to occasionally tow within the truck's chassis/frame limit. If we wants to tow a lot, then the 11-½" axle may be a good upgrade. It's not really any stronger than the 10-½" 14b, but the bigger ring and pinion allow more power to be put through the gears on a continuous basis without the metal at the tooth contact surfaces exceeding the 350°F surface temp limit. OTOH, Ford continued to use a 10-½" ring and pinion in their Sterling axles after GM and Dodge had gone to the 11-½" AAM in their diesel 3/4 and 1 ton trucks, and despite having similar HP and tq and GCWR as their rivals they had no issues with R&P failures, so I'm not convinced the 11-½" would be needed even if towing within the truck's limit continuously. Biggest thing with any axle is to monitor fluid temp if it's a concern, and keep it under 230°F.
 
#28 ·
Just a general comment. Both the Dodge airport tug and the IH street sweeper were designed to move at walking speeds. Both will be "specification" vehicles (Translation: Designed with the lightest (i.e. cheapest) components to bring the cost down to a competitive bid). And the rear axle ratios will be wrong for highway speeds.
 
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#29 ·
Hi Russ,
The airport tug has a Dana 70 in the rear with a 7.16 gear ratio! So yeah, it's not ideal to say the least.
It's already been swapped out for a GM 14 bolt with 4.10 gears so it should drive decently.
As for the street sweeper, I'm only looking for the transmission (the Allison) to manage the expected bump in torque from the 5.9 and the extra gears.
Worst case scenario, I'll at least have the Allison housing which I can later have rebuilt with better internals.
The Tf727 that came in the tug truck won't do the engine (or itself) any good at highway speeds.
 
#32 ·
After a lot of research, I managed to track down a 6 speed Allison 1000 from what I believe was a 2007 6.6 Duramax. The trans itself is July 2007 build. It's a 2 wheel drive trans but that will have to do for now, given the circumstances. It's missing the harness (it shouldn't be hard to buy one online?). I'm not sure about the TCM if it's there or not, but would it be a problem if I bought the trans without it? I don't think I'll ever reflash the stock TCM myself or even find someone who would do it without messing things up first. From my understanding I can buy an aftermarket standalone controller, that would come pre-flashed, am I m

My question is, would I have any issues fitting this specific trans to my Cummins (It's an 89 12 valve non-intercooled, intercooler will be added later)?

And what parts would I also need to make the swap. I know this may have been asked a few time before but I can't seem to make a definitive list of parts that I will need to make the swap. Other than the trans adapter and necessary flexplate/bolts, what else would I need (TCM, wiring harness,...etc)? What about throttle input for the trans?

The engine and trans are going into a 1978 Dodge truck, so there shouldn't be any major electrical issues, everything is pretty much mechanical, so I shouldn't have to hack into the wiring harness to make it work with an ECU/ECM.

Any input would be appreciated, I'm about to pull the trigger on the trans but I need to make sure I have everything else to make the swap go as trouble-free as possible.

Excuse the low quality pics, I was sent them by the guy who's selling. I'll go see it in person if it's the the right transmission.
 

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#41 · (Edited)
After a lot of research, I managed to track down a 6 speed Allison 1000 from what I believe was a 2007 6.6 Duramax. The trans itself is July 2007 build. It's a 2 wheel drive trans but that will have to do for now, given the circumstances. It's missing the harness (it shouldn't be hard to buy one online?). I'm not sure about the TCM if it's there or not, but would it be a problem if I bought the trans without it? I don't think I'll ever reflash the stock TCM myself or even find someone who would do it without messing things up first. From my understanding I can buy an aftermarket standalone controller, that would come pre-flashed, am I m
A stand-alone harness and TCM can be purchased separately if necessary. If you buy one of the medium-duty controller setups, then they will supply a harness and suitably flashed TCM as needed. That is all relatively straightforward. It just costs money.

My question is, would I have any issues fitting this specific trans to my Cummins (It's an 89 12 valve non-intercooled, intercooler will be added later)?
It's been done umpteen times. Why do you think there would be a problem fitting it to your specific engine?

And what parts would I also need to make the swap. I know this may have been asked a few time before but I can't seem to make a definitive list of parts that I will need to make the swap. Other than the trans adapter and necessary flexplate/bolts, what else would I need (TCM, wiring harness,...etc)? What about throttle input for the trans?

The engine and trans are going into a 1978 Dodge truck, so there shouldn't be any major electrical issues, everything is pretty much mechanical, so I shouldn't have to hack into the wiring harness to make it work with an ECU/ECM.

Any input would be appreciated, I'm about to pull the trigger on the trans but I need to make sure I have everything else to make the swap go as trouble-free as possible.

Excuse the low quality pics, I was sent them by the guy who's selling. I'll go see it in person if it's the the right transmission.
This has all been covered numerous times in this thread, but here it is again:

1) You need to mount the transmission to the engine. You have two basic options: Either use SAE #3 (SAE #2 is too big for most pickups) or the GM bellhousing.

If you choose SAE#3, you need the SAE#3 flywheel housing for a B series front gear train engine, SAE #3 bell housing for the Allison, SAE #3 flexplate and converter/flexplate pilot for the Cummins B series, and the SAE #3 flexplate-to-converter mounting ring (a conical shaped ring that attaches the converter to the flexplate). That is five components. You also need the particular starter for whatever SAE #3 housing you get. I would highly recommend ONLY using an SAE #3 housing with a left-side mount starter to avoid exhaust interference. You will likely have to do some removal of various mounting bosses and protrusions on the flywheel housing. Not a big deal.

If you choose to go the GM bellhousing route, then your only realistic option is the Destroked flywheel housing and flexplate kit. It uses the GM bellhousing already on the 07 Allison you are looking at. The other item needed is an expensive Ford 6.0 Powerstroke starter, which mounts on the right side. You can get the whole kit and kaboodle from Destroked; adapters and electronics for stand-alone operation. I don't personally care for the Destroked stuff (or anyone else's stand-alone solutions for that matter), but it more or less works and is the easiest way from A to B if you want to stick with the GM bellhousing and not shop separately for your electronics. Note that you CAN use the Destroked adapter hardware and another outfit's electronics, or vice-versa. Most guys choose a single source for everything though, for obvious reasons.

2) You need the electronics. ALL controllers will use the OE Allison TCM. There's three basic methods in use: the first is to use a medium duty OS in the TCM which takes throttle inputs directly from a potentiometer-type TPS. Every one of these I have driven shifts just like a medium duty truck, which is to say it shifts like a GM Allison TCM stuck in tow/haul mode. I'm also pretty sure they have no option for a 4WD low range shift schedule. This isn't tragic, but it's nice having a softer shift schedule with different shift points in low range, as well as being able to run the output speed sensor on the t-case output rather than scabbing it into the trans-to-tcase adapter.

The second control option is to use an 8.1L gas OS in the Allison TCM. This gives all the goodies of a GM TCM cal, and allows you to use a common off-the-shelf Cat (or Ford, according to some folks) TPS with a PWM output. The two main complaints with this option are lack of tow/haul without wiring in a compatible BCM or some other box to communicate tow/haul button requests to the TCM, and the fact that the TPS input doesn't give full range on the TCM input. As mentioned, tow/haul can be done with extra boxes and wiring. The apparent limit on TPS input range can be worked around with proper scaling of the calibration tables. It isn't a perfect option, but it does get the job done and I have a few trucks out there running with this setup that I did in years past.

The third option is to use a TCM with the GM OS used in Duramax applications. This requires an interface controller capable of sending the required signals via GMLAN to the TCM. I'm not sure if the Destroked kit uses this method, or method #2 with an auxiliary box, but either can work. If the interface is done correctly, you will have access to all features of the GM OS in the Allison TCM. If it's done correctly AND you have electronic engine controls then you will also have defuel capability, which massively increases the amount of torque the trans can reliably handle.

That's pretty much it.
 
#35 ·
Being on the other side of the world does put you at a disadvantage. You have a 2wd 6 speed Allison 1000 with no control module or wiring. OK. First issue is mating it to your engine. First option would be install an SAE3 bellhousing onto the 1000 and use Cummins SAE3 engine adapter parts. The 1000 was commonly used behind some of the Cummins ISBe 4 cylinders and have seen a few on 4bt's. Second option is get a custom adapter for the GM Allison to mate to your engine. A company here in the US named Destroked has all the parts. The block adapter plate is $795 which includes the bolts. The flex plate is $625. The starter for that setup is a Ford 6.0 diesel type that they sell for $179. I assume you have the torque converter. This get your transmission mated to the engine. They also have the stand alone control unit for the 6 speed. That's $1599. Ouch. There may be some sensors you'll need to attach to the engine and those may be included there. You'll need a shifter of some type. Not sure if your old Dodge unit will work. Destroked could tell you. Now after spending around $3200 you have an operational transmission mated to the 6bt. If you wanted to change it to a 4wd unit, that can be done as well. You'd need to replace the transmission rear housing and output shaft. That process must be done with the transmission standing on its end. The updated 4x4 housing is in the $500-600 range and the output shaft around $650 for a high quality billet unit. Of course you'd need a GM transfer case to match up. God only know what the freight from the US would be. Got any friends in the military over there who could bring it in with a shipment? Here's a link to Destroked. Allison 6 Speed controller
 
#36 ·
Being on the other side of the world does put you at a disadvantage. You have a 2wd 6 speed Allison 1000 with no control module or wiring. OK. First issue is mating it to your engine. First option would be install an SAE3 bellhousing onto the 1000 and use Cummins SAE3 engine adapter parts. The 1000 was commonly used behind some of the Cummins ISBe 4 cylinders and have seen a few on 4bt's. Second option is get a custom adapter for the GM Allison to mate to your engine. A company here in the US named Destroked has all the parts. The block adapter plate is $795 which includes the bolts. The flex plate is $625. The starter for that setup is a Ford 6.0 diesel type that they sell for $179. I assume you have the torque converter. This get your transmission mated to the engine. They also have the stand alone control unit for the 6 speed. That's $1599. Ouch. There may be some sensors you'll need to attach to the engine and those may be included there. You'll need a shifter of some type. Not sure if your old Dodge unit will work. Destroked could tell you. Now after spending around $3200 you have an operational transmission mated to the 6bt. If you wanted to change it to a 4wd unit, that can be done as well. You'd need to replace the transmission rear housing and output shaft. That process must be done with the transmission standing on its end. The updated 4x4 housing is in the $500-600 range and the output shaft around $650 for a high quality billet unit. Of course you'd need a GM transfer case to match up. God only know what the freight from the US would be. Got any friends in the military over there who could bring it in with a shipment? Here's a link to Destroked. Allison 6 Speed controller

Thanks for info Char1355,
Seeing as the trans I mentioned doesn't come with the bellhousing, I was thinking of going aftermarket from the beginning, that's of course including buying the flexplate, bolts and Ford starter. As for the standalone controller, I was looking into getting the Transmissiontuner kit, it's still not cheap at $1100 but it's cheaper than the Destroked kit and I've read good things about them on this forum. Not sure if you'd advise me to go this route or not.
I'm mostly worried about the sensors, as I know it'll be the thing that will really slow down the project. If there are part numbers and instructions on what to do, it shouldn't be a problem. Do you happen to have part numbers?
If that's literally what it'll take to make the transmission work properly with my engine, without the need to custom fabricate parts (other than a cross member), then I'm gonna have to bite the bullet and buy the things.
I'll forget about the 4 wheel drive for now, I just want the truck to move under its own power for now.
Shipping won't be cheap, but I'll see if someone is willing to share a container with me.
Am I missing something? I apologize if I'm asking the same questions, but I just want to make sure I have everything before buying the transmission.
Thanks again
 
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