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Discussion Starter · #21 ·
4l80e High torque build

Here are some updates on my build.
I found a lot of good info on the 67-72 Chevy truck 4l80e/TH400 page that helped me alot with my tranny build. Been working on my 4l80e build and wanted to share this with yall wanting to build a stronger 4l80e.

Update on my transmission build I ordered a stage 5 kit from Jakes Performance. The superdrum that Jakes Performance sent was not what I expected. I thought I would get a custom built in house by Jakes using a stock drum with a 36 element sprag but after waiting 45+ days to receive its only a BTE TH400 drum 36 element drum that uses smaller custom intermdiate clutches that really doesn't fit 97 and up units. I decided against running it and regret ordering it.

I ordered Jakes re calibration shift kit when I placed my order. But after a lot of reading up on this I am thinking that hard shifts on a heavy truck will most likely kill the 34 element sprag and be harsh on hard parts. I decided not to run it even though Jakes said it would be fine. Instead I am going to run the stock separator plate, all accumulators and drill the 2nd, 3rd and 4th feed holes about 30% larger.

I know a lot of people on here and other sites think very highly of Jakes Performance but I am here to say it has not been a good expereince! The guy who placed my order has very little knowledge of transmission building and Jake I guess is to busy to give you a few minutes of his time to help you get what you need and not sell you things that you dont need.

My experience with TCS in Canada wasn't great as well.
I called them back about the planetary I purchased from them not having the lube slots cut in shown in their picture on their websire. Explaining that on the 1997 and up need these slots in order to lubricate the bushing and thrust bearing in the forward drum. Without these slots on a 97 and up unit the bushing and bearing would very quickly destroy their planetary, and the foward drum at a minimum.
Basically to be told they don't build transmissions and the picture is old they have sold bunches of these without lube slots with no issues and the best they can do is allow me to send it back. After studying this issue I believe that running a hollow main shaft would allow lubrication to the forward clutch bushing and thrust with out the lubrication holes. So since the Jakes performance main shaft is hollow (The Jakes performace billet main shaft was also .110 longer that the orgininal and hollow and had to be shortened to keep from it bottoming out on the input shaft)

I included a few pictures of what failed in my tranny. Evidently water had gotten in it before i bought it and rusted several parts. The thrust bearing failed on the forward clutch I believe due to rust on it. Surprizingly this thing drove for 2 years before it quit.
 

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Discussion Starter · #22 ·
Really happy with the way my transmission turned out. The Precision Industries converter is pretty nice too. The picture of the valve body shows the Sonnax overrun clutch kit. Should be beneficial in preventing a overrun clutch failure.


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The big test will be to see how it lives with a high performance 6bt. Even with performance building, not sure what the limits of the 4L80e are. Only time will tell.
4L80e, has its limits, on diesel applications "because of torque output not HP".
I had a built 4L80e, but was not convinced it would work with the 12 valve conversion, so I built my own 47/48RE hybrid, w/ low stall billet converter and never looked back.
 

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Subrutus, people always seem to be looking at HP but that's not what diesels, especially Cummins, are about. The Cummins is favored because of it's tremendous torque which is what will destroy a lot of automatics because it happens at such low RPM. Allison, Dodge, and maybe a few Ford transmissions can be built to handle very high power output. Have to notice that GM uses the Allison on its diesel pickups so that sort of tells the story. Even with manual transmissions there are limits. I believe all the big 3 have abandoned manuals now.
 

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Subrutus, people always seem to be looking at HP but that's not what diesels, especially Cummins, are about. The Cummins is favored because of it's tremendous torque which is what will destroy a lot of automatics because it happens at such low RPM. Allison, Dodge, and maybe a few Ford transmissions can be built to handle very high power output. Have to notice that GM uses the Allison on its diesel pickups so that sort of tells the story. Even with manual transmissions there are limits. I believe all the big 3 have abandoned manuals now.
I was debating using the Allison, however, I had read that it has some serious parasitic side effects, as opposed to the 48RE...a controller for the Allison was the other issue I had faced too..."I do like the Allison".
Stand alone controllers for the 47/48re are around $800 USD, and can be adjusted for whatever task is at hand for those transmissions.
When I was working on may conversion, I tried to use the 47RH, which was too long for my build, the 47/48RE were just the right length, so I did not have to relocate, my drive train and torsen bar cross members.
 

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Haven't really heard much about parasitic effects on the modern Allisons. Any in the 1000 series or higher have lockup torque converters and offer different torque converters depending on engine and application. Their big issues are sheer size and cost. The controllers hit in that cost area too. About twice the price of one for other automatics. Also, most companies don't make many upgrade parts for the Allison. The Allison 3060 came behind the 6bt in trucks and motorhomes but most vehicle don't have room for a 400 lb transmission. Also, so many of the vehicles in swaps are 4x4 and the 1000 series is about the only one with that feature available. Didn't realize the 47RE was any shorter than the 47RH. Thought those two were the same except for electronics.
 

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Haven't really heard much about parasitic effects on the modern Allisons. Any in the 1000 series or higher have lockup torque converters and offer different torque converters depending on engine and application. Their big issues are sheer size and cost. The controllers hit in that cost area too. About twice the price of one for other automatics. Also, most companies don't make many upgrade parts for the Allison. The Allison 3060 came behind the 6bt in trucks and motorhomes but most vehicle don't have room for a 400 lb transmission. Also, so many of the vehicles in swaps are 4x4 and the 1000 series is about the only one with that feature available. Didn't realize the 47RE was any shorter than the 47RH. Thought those two were the same except for electronics.
The 47 RH 4x4 had a longer 4"+ O/D section, than the 47/8RE to house the hydro gov unit.
 

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Been wanting to up the power to the 500hp range at 3000rpm. It will be for daily / weekend driving fun. I posted this on my build page as well. Please advise.

As far as my long-term goal for more horsepower goes I have several obstacles to overcome a little at a time.
1. Lift pump- I think the aftermarket fuel lift pump is not up to the challenge. I have read that there is a Cummins factory pump with a certain cast number that will do the trick. Planning on changing this soon. The trick falls on its face around 3000rpm. I plan on tapping into the pump supply with a gauge, so I will know for sure where the fuel pressure is and know if
2. Head gasket issues- I milled the head and ran a Felpro gasket that looked like a OE. Big mistake. With 19 degrees of timing when running it hard it lifts the head and a small amount of coolant leaks from the rear of the head even with ARP studs. I lubed and retorqued all the bolts one at a time with no luck. So, to correct this I ended up dropping the timing to 16 degrees. But to achieve the HP / RPM goal. I am thinking that the timing will need to be in the 19 to 25 degrees. So, a new Cummins OE head gasket is what I am thinking about trying to accomplish this. I see a few posts about the Victor / Mahle gaskets working ok but I am not sure if that is the case at this performance level. I lapped the valves when the head was off in the previously but still had a few minor pits I couldn’t remove. Maybe this go around I should fix this and polish the head a little better as well.
3. Transmission upgrades- Torque converter is a Transtar billet piston converter that is a little loose for my liking. Tranny is a stock 2003 4l80e I was told had low mileage. So, I been researching what is needed to make it hold more power. So, I am thinking that I can get a triple disk torque converter from Jake’s Transmission. Use their upgraded input shaft, dual feed the direct drive and ask for any other hydraulic improvements they recommend. The other option is to buy a complete stage 2 or 3 kit from Jakes.
4. Drive train – Run a set of custom Reaper traction bars to prevent axle wrap after getting the pinion angle where is needs to be. I still need to research this but I am thinking that a transfer case brace would be a good idea to. It’s a long setup with the 4l80e np205 and GV OD. I am also concerned the u-joints may not hold. Still running the stock u joint I think it’s a 1350 greaseable joint. I am wanting to do some searching for a stronger non-serviceable joint. When my rear drive shaft was built I requested for a HD tube. Not sure what they used but he was confident it would hold.
5. Fueling- Currently I am running the factory 180 delivery valves and 5x9 factory injectors. I am thinking about going with a 500 or 550 hp fuel set up from Power Driven Diesel. Kit includes injectors 5x12 and 025 or 7mm DVs. Then I would like to put it on a dyno and see what it does. If I am not happy with it a compound set up would be the way to go but I seen some dyno pulls done by PDD with a gated S362 with a tight turbine housing. Seemed like it is exactly what I need without the trouble of fitting a second turbo.
This is all a trial and error so please if you have any advise from similar set ups please share it.
On the Trans question #3. If you want 500HP, look at the torque of that first, then shop transmissions. Most builders can get you exactly what you need based of torque. For what its worth, spend the extra for the triple disk billet, IMO, for the piece of mind, even if your not using to pull heavy loads from a dead stop romp. I have not tried an upgraded 4l80e yet, but the trans should have atleast the hardened input shaft, and billet drum. Every performance 4l80e rebuilt trans I have studied so far has all the major fixes and correct updates done to them. Jakes trans website has been listing the transmissions as having some supply chain issues with parts FYI. Check out Monster Transmissions, Transmission Depot, and Mad Dog transmissions. Good luck, and remember, Im not a transmission expert!!! Research is
key.
 

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You have to figure that a Cummins at 500 HP will have over 1000 lb ft of torque coming full on at around 1700 RPM. I don't think any 4L80e is going to live with that. At least not without some major modifications. Even an Allison in the 1000/2000 series will need mods to live with that.
 

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Here are images of the 47rh & 47/48re O/D units.
Green Blue Motor vehicle Gas Water
Bumper Gas Auto part Automotive tire Font
 

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That's a pretty significant difference in length. If you were dealing with a short vehicle, would have to consider the RE series even though you'd need a control unit.
Yes Sir, I was given bad information, back when I started my conversion, finding the longer RH version would not work, for my application.
The shorter case allowed me too use all the cross members too include IFS, in the same stock locations on the chassis used for the factory drive train. No drilling holes in chassis, or moving IFS torsen bars from their designed locations.
 
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