[MaxPF]

Do you have someone who can plug in a scanner and pull the fault codes?

 

[edpruss]

I have a spare Allison PTO.

Ed

 

[fullcircle]

Do you have someone who can plug in a scanner and pull the fault codes?

Problem is the harness does not have a computer port/plug on it. Might need to wire that in

 

[wrenchtech]

I’m sure the answer is somewhere in this excellent thread, but I don’t think I can read 39 pages right now, so I will just ask. Is there a way to do a Cummins swap into an early 2000 Ford F-250 super duty, using off the shelf parts, to run an Allison automatic? Maybe using an SAE #2 bellhousing and a flex plate and torque converter from a medium duty application?

 

[MaxPF]

Yes. OE MD Cummins and Allison 1000/2000/2400 combos use SAE #3 flywheel housings.

 

[Compulsion2Mod]

I'm working on a 5 speed Allison swap that I can't get out of limp mode. Everything seems like it's right, but it still doesn't work. It's an 01 trans with an 01 tcm from an 8.1 truck. I've got a Tech 2 and everything looks good, but when I select reverse, it commands neutral, and when I select drive, it commands 2nd. I'm pulling my hair out over this thing so hopefully someone can give me some words of wisdom. There is one thing that is odd, and maybe someone can tell me if its right or not. The case of the tcm that says "do not ground to chassis" shows continuity to the chassis ground with the plugs plugged in, but if you unplug them, it's not grounded. Is that how it normally is, or is something wrong with my tcm?

 

[MaxPF]

The most common cause of such problems is the NSBU switch. If the retaining screws are loosened it can be rotated a bit. With the trans in park, try adjusting it's rotational position. It could also be the adjustment of the shifter/shift cable itself. In fact, if no codes are being thrown then the shifter or cable being out of adjustment is most likely.

The TCM case should not be grounded. Mount it on rubber or plastic isolators. I do believe the case will show continuity to ground with the harness plugged in, but it is grounding through the MOSFET drivers. Thats why the case must be isolated.

 

[Compulsion2Mod]

Thanks for the reply Max. I went to replace the internal harness because I noticed I wasn't getting a temp sensor reading, and I had a slight leak through the plug, and when I pulled the pan off my Craig's List transmission, I saw that the psm was completely MISSING! I bought one of those and put it on, and bam, I've got reverse and 1st gear!

Now I go to drive it and it is randomly commanding neutral. I'm guessing that I do in fact also have a bad NSBU, or possibly even the wrong one. It wasn't actually bolted on when I bought the trans, so who knows what's up with it. I guess I'll replace that and see what happens.

My only other question is about the torque management. I'm using the stock 8.1 programming right now. Would the torque management react badly and randomly command neutral? I've got the unmanaged torque wire tied into the Cat tps connection as outlined earlier in the thread.

 

[MaxPF]

Problems with the NSBU should throw a DTC, and it wouldn't cause the trans to go into neutral. In fact, the computer cannot command neutral in the 1000/2000/2400 series. It can only be selected by the manual shift lever. This doesn't mean a malfunction couldn't cause the trans to not engage an oncoming clutch, just that the TCM cannot specifically select a neutral gear. You need to describe more thoroughly what it is doing.

Torque management won't do anything if the engine doesn't have the ability to reduce torque by command. The TCM may expect reduced torque input and you coud get a "flare" during the shift, but the TCM should learn and tighten it up unless your engine is putting out substantially more torque than a stock 1000 is rated for (600+lb-ft).

 

[Compulsion2Mod]

When it drops into neutral, it seems to usually be at a low speed, low tps situation. If I pull it into reverse to back out and just ease into the throttle, it will usually go to neutral before I get completely backed out of the drive, and I look over at the Tech 2, and it says gear selected - 7 (reverse), gear commanded - 0 (neutral) . If I pull it into gear and stab the throttle pretty hard, it will usually stay in gear until I let off and get almost completely stopped. When it does go into neutral, I can shift to any other position or to neutral and back where it was, and it will go into gear again, no restart required. I haven't been able to drive it much, but I don't think it has ever happened at more than 7-8% TPS.

That's good to know on the torque management. That's been my main concern since I started the swap, but sounds like that's nothing to worry about for me. I've got it behind a mechanical 6.5l TD, so it's 400 lb.ft. or less.

 

[MaxPF]

That's a new one on me. I misspoke when I said that the TCM cannot command neutral. Technically, it can and does in park or neutral, but the manual selector switch also controls the neutral hydraulic flow. The TCM should never command the neutral solenoid combo (all three shift solenoids active) when the NSBU/IMS indicates a valid forward or reverse gear is selected. Since your Tech II says that reverse is selected, that leads me to believe the NSBU is working properly. No guaranteed, of course, but as I said a bad NSBU will typically throw a code because there will be a mismatch between the gear it says is selected and the hydraulic info being given by the PSA. Are you certain there are no DTC's?

 

[wrenchtech]

Yes. OE MD Cummins and Allison 1000/2000/2400 combos use SAE #3 flywheel housings.

Thanks for being a good sport and letting me bounce these questions off of you. Finding definitive answers on these questions is not easy. So now I am pretty sure that an Allison 1000/2000/2400 uses an SAE #3 to get paired up with a Cummins 6B/4B variant engine, my next question is will one of these transmissions with this bellhousing fit in the transmission tunnel of a Ford super duty pick up truck.?

 

[Compulsion2Mod]

There are no DTCs, but I've done a little more diagnosis. I checked the part # on my NSBU, and it is for a 4L80E so I ordered the correct one and installed, but no difference. I drove it a little more, and I cannot get past 2nd gear. For some reason the trans cannot "see" it shift to 2nd, so it never commands 3rd. When I get the shift to 2nd, the Tech2 still says, current gear is 1. I thought the PSA was supposed to tell it what gear it is in, and it is new as well as the internal wiring harness, and I've double checked both ends of both harnesses and everything goes where it is supposed to. Could there be something in the valve body messed up not showing the PSA the proper pressures?

Also, I've noticed that when it drops itself into neutral, it looks like the speed signal is going away. I'm using a pulse generator on the cable drive of my np205 for the output speed. For some reason it is slow to show output speed. It usually will read either 0 or 29-30 rpm when I'm stopped and won't pick up actual speed until its getting 400-500 rpm on the output. Is anyone else using one of these Dakota Digital pulse generators successfully? I need some words of wisdom...

 

[MaxPF]

Thanks for being a good sport and letting me bounce these questions off of you. Finding definitive answers on these questions is not easy. So now I am pretty sure that an Allison 1000/2000/2400 uses an SAE #3 to get paired up with a Cummins 6B/4B variant engine, my next question is will one of these transmissions with this bellhousing fit in the transmission tunnel of a Ford super duty pick up truck.?

The SAE 3 is most common, but SAE 2 is also available for the 1k/2k series. I have never seen one myself, but the part number exists in the book. Every Allison 1K/2K I have seen behind a Cummins has been SAE 3.

The trans should fit in a Super Duty just fine. It's no bigger than the ZF 6 speed manual. Biggest fitment gotcha will be the SAE 3 flywheel housing that bolts to the engine. They are bulky and usually have big mounting pads on them that often need to be cut off for fitment in pckups. You can get it to fit, but you may have to do some firewall/front tunnel massaging, a 1" body lift, or other minor mods. Nothing insurmountable. Just try it without any mods first and see if there is a combination of engine position (height, setback, angle) that lets it fit without mods. If not, mod as needed.

FWIW, I am in the planning stages of a swap myself. Once again, my old ankle injury is rearing it's ugly head and I think working the clutch is just aggravating rather than exercising it. I was prepared to do the swap years ago but ended up keeping the manual and selling the swap off. The new swap is planned to be a 2010-up GM 1000 with the variable line pressure valve body and HD 4WD tailhousing. However, that depends on whether the Allison SAE 3 bellhousing will work on the newer GM 1000's. I'm still researching that part. Anyway, I intend to either make an adapter ring for the Dodge flywheel housing to SAE 3, or fabricate a shorty SAE 3 housing from scratch. The standard SAE 3 housing is too darn long and bulky for my truck, but otherwise the round configuration that fits tight to the converter is ideal. I don't want to use the GM bellhousing because I don't want the starter on the pass. side where I have to run exhaust and other items.

 

[MaxPF]

There are no DTCs, but I've done a little more diagnosis. I checked the part # on my NSBU, and it is for a 4L80E so I ordered the correct one and installed, but no difference. I drove it a little more, and I cannot get past 2nd gear. For some reason the trans cannot "see" it shift to 2nd, so it never commands 3rd. When I get the shift to 2nd, the Tech2 still says, current gear is 1. I thought the PSA was supposed to tell it what gear it is in, and it is new as well as the internal wiring harness, and I've double checked both ends of both harnesses and everything goes where it is supposed to. Could there be something in the valve body messed up not showing the PSA the proper pressures?

Also, I've noticed that when it drops itself into neutral, it looks like the speed signal is going away. I'm using a pulse generator on the cable drive of my np205 for the output speed. For some reason it is slow to show output speed. It usually will read either 0 or 29-30 rpm when I'm stopped and won't pick up actual speed until its getting 400-500 rpm on the output. Is anyone else using one of these Dakota Digital pulse generators successfully? I need some words of wisdom...

If it's losing speed signal that may certainly be the issue. You need to figure out why that signal is going away. Did you use a twisted pair of wire going from the sensor to the controller? Non-twisted pairs will pick up noise and screw up the works.

 

[Compulsion2Mod]

It was the speed sensor signal that was the whole problem. I eliminated the Dakota Digital setup and installed a factory tone wheel on the driveshaft carrier bearing. Then I fabbed a bracket to hold a factory speed sensor and voila, it shifts through all the gears and hasn't dropped into neutral once! I'm hoping my external speed sensor will be reliable, but if not, I guess I'll have the 205 machined for a factory style vss. At least now I know everything works even if it needs some tweaking here or there to be actually "finished". Thanks Max for your responses as well as all the work you put in to get this thread started, what a great resource!