Allison Help

[Dustin1016]

Not sure if I have an Allison issue or Duramax issue? 2011 Chev 3500, driving emergency brake and ABS light came on. Shift indicator line went blank. Truck would not upshift, eventually insidcator light came back on and truck shifted normal. Now the indicator is off again, other 2 lights still on, truck hard going into reverse or drive, but when the shift indicator light is on it shifts smooth. Thinking possible TCM but unsure, and would TCM cause the other 2 lights to come on? Havent found any obvious wiring problems or damage.

 

[Mike L.]

any codes?

 

[Dustin1016]

U0101 is the only code I could pull

 

[Mike L.]

U0101 is the only code I could pull

Communication problem. grounds or TCM problem.

 

[Dustin1016]

Is there a schematic available online? Troubleshooting tree for TCM? Unsure where all ground locations are to check. Never had any other symptoms or major issues and for all to happen at once was very odd.

 

[onebaddmaxxx]

What kind of scanner are you using? I can give you a flow chart when I get home for the code

 

[Dustin1016]

Not sure, just stopped by a local parts store and had them hook up their scanner.

 

[Mike L.]

Not sure, just stopped by a local parts store and had them hook up their scanner.

That's not good enough for diagnosing.