TCM Update?

[Chris611]

I have an '02 Dmax/Allison. Stock engine with a health EFILIVE tune. Stock trans. It a dedicated puller. I have about 35 hooks on the setup and it looks like my trans is done. I've talked with Mike L who was very helpful and also had a local guy scan it with a Tech II per Mike suggestion. Neither the Tech II or EFILive is showing any codes. It has never gone into limp mode and there are no CEL. I feel it's slipping because when I powerbrake it, it will try and push through the brakes until I keep adding throttle, then all of the sudden the RPMS go up and the truck "relaxes" and stops trying to go through the brakes.

I am figuring on adding a suncost iv kit, but here is my concern. The fact that I got no codes, what does that mean? Is there an update to the TCM that needs to happen, is my TCM bad? I just don't want to build the trans and still have some other issue. If I disconnect the round connector on the trans and run the truck, I get all kinds of codes, so the TCM is at least alive.

Thanks

 

[THEFERMANATOR]

Possibly thet rans isn't slipping, but the torque converter is toast. The TCM will only show slippage if it is sensed between the input and output speed sensors. If it is between the turbine speed and input then it wouldn't code as it would just see the torque converter slipping like it is supposed to. Or you could have a problem in your transfer case, but this will normally code.

 

[x MadMAX DIESEL]

I would say its the TC slipping aswell, do you have the actual EFI Live V2 or just a tune? If you have the software plug in the v2 on the street and give it some WOT runs, data logging TCC duty cycle and TCC slip rpm. I know from experience that these converters can slip BAD for a good amount of time before ever showing any type of TC related code.

 

[Chris611]

I have the V2 and have logs of the trans. You mention doing WOT runs. I have the truck setup for pulling now and it's not able to get on the road. Is there anything I can do in 1st or 2nd gear to determine if the TC is bad?

 

[Chris611]

I just did a little testing. I put it in reverse and stood on the brakes. I then pushed on the throttle. I can mat it and the rpm's will on climb to about 2000 rpm. If I go forward the rpms will climb much higher than 2000. Do these test rule out tc failure?

 

[THEFERMANATOR]

Not really. What does your ISS and turbine speed sensors read when it flashes the RPM's up? If you are on the brakes and not moving, then your ISS should be 0 until it begins to move. Then your ISS and OSS will begin to climb.

 

[Chris611]

Here is a screen shot of the log file. Just to the right of the 100 second mark is where it started to slip.

 

[Chris611]

Well, I keep trying things before I pull the trans. My biggest concern is if something is wrong with the TCM that it won't show codes, I want to get that fixed before a trans build. I unplugged the trans input speed sensor (about 10 o'clock on the trans housing) and got a TCM 0727 code although no CEL came on. Next I plugged that back in and unplugged the speed sensor on the transfer case, I don't get any code with that. If I back up after about 10 feet the truck stops moving and the "R" flashes. If I watch the output in Scantool, it shows no speed (which is correct since it's unplugged), so shouldn't I get a code for that? Next I unplugged the turbin sensor and Scantool showed 0 on the readout, however got no code there. I only went back and forth about 20'. Shouldn't that be enough to trigger a code?