Allison 5sp: No forward gears after mild 4wd launch

[CarolinaHD]

Hey guys trying to help a local member who posted over on diesel place. He lost all forward gears but still has reverse. I hooked up my tech 2 and pulled out 19 codes in the history and then 4 more popped up that are current. Truck is a 2005 and supposedly has a built transmission from the previous owner, but we all know how that goes...

Current codes
P0711
P0717
P0721
P0722

Original thread from dp.

http://www.dieselplace.com/forum/63...ibited-after-mild-4wd-launch-tranny-limp.html

Thanks..

 

[CarolinaHD]

Trans code history-

U1096
P0872
P0870
P0847
P0845
P0777
P0776
P0773
P0768
P0747
P0746
P0743
P0741
P0735
P0734
P0733
P0732
P0731

None of these codes are current, all are stored in the history.

 

[Mike L.]

Check all grounds and make sure the trans is getting 12V while engine is running. Try another TCM after that.

 

[CarolinaHD]

Thanks Mike I'll pass along the info

 

[TheBac]

Wow, he ended up with 19 codes. Damn.

 

[Mike L.]

Wow, he ended up with 19 codes. Damn.

Usually an act of God or electrical problem.

 

[KyleC4]

I always recommend too doing a voltage drop on grounds and testing 12v circuits with a test light. Need to make sure circuit can drop 12v

 

[CarolinaHD]

Thanks for the info, I figured from the start it was electrical or he just broke everything inside of it lol.