Allison 5sp: Need help 02 Allison

[Racer11]

Need help with 02 Allison, new to this whole diesel thing. I just got a 02 duramax with a Allison that is in limp mode. Code po872. The gentleman I got it from had trans rebuilt, new n/s switch, new silenoids twice, new tcm. All with under 10 miles on it. The gentleman he got it from also had trans rebuilt with same outcome so now it's my turn to give it a whirl. I am a mechanic but don't know a lot about max's or allisons. If I had to guess from my experience I would start with wiring. Any help would be greatly appreciated. Thanks

 

[onebaddmaxxx]

Your E shift valve is stuck.

Located in the top half of the valve body.

 

[Racer11]

It was replaced twice by trans shop

 

[onebaddmaxxx]

Your original post says the solenoid was replaced twice.

Im saying the shift valve is stuck.

 

[Racer11]

They tell me it was replaced twice also plus did it with old tranny also this is a complete different trans and it was replaced in the old trans same problem trans shop tour old trans down didn't find any problems with it

 

[THEFERMANATOR]

E shift valves don't get replaced, I don't think they can even be purchased seperate of the valve body. I'm willing to bet you have a burr or gall in the bore of it, and need a reamer to clean it up if it is in fact your e valve sticking.

 

[Mike L.]

You can buy new E shift valves from Allison.

 

[onebaddmaxxx]

You can buy new E shift valves from Allison.

Yes and they are cheap like $7 if I recall

 

[THEFERMANATOR]

You can buy new E shift valves from Allison.

Last time I called, the parts guy laughed when I asked. I just clean them up and re-use.