[SGT_BlackSmoke]

While driving home from work I noticed my truck did not want to shift correctly, it actually failed to shift at one point and I had to put it in neutral to reset and then back into Drive to continue driving. I attempted to use tow haul to utilize the Torque Converter more to save stress on the transmission, it actually kicked it out of tow haul. It then threw some lights at me for the ABS and a few others but not the CEL. Here is a list of codes I received
U0101 Lost communication with the transmission
P0880 TCM Power input Signal
C0055 Rear wheel speed sensor circuit malfunction
B2725 Active transfer cse Mode Sw Circuit Signal Invalid

Sounds like an electrical issue to me, maybe a bad harness, or lose connection. Any help is greatly appreciated, I just paid this truck off seems like perfect timing.

2008 Chevy 2500 Silverado Duramax

 

[Bsimster]

Either harness or a bad ground. I hate electrical gremlins. Good luck!

 

[Ron Nielson]

And here is some more info on steps that may lead to your problem resolution.

 

[SGT_BlackSmoke]

Thank you!

 

[SGT_BlackSmoke]

So after looking into this. I think it may be a simpler fix than chasing wires! But hopefully no serious damage has occurred. I chased the wire harness down and no loose connections were found. I took it for a drive. And it drove fine... until I pulled in the drive way and slowed down and then it fell out of gear and instructed me to shit to neutral before continuing. I did this and it fell out again. I shifted to park and then back to drive and it moved. So I checked the transmission fluid and by now the tranny was 110-115 degrees. The dip stick only indicated tranny fluid to the “cold” mark and not to the “hot” mark. Which is quite a difference! So I’m hoping this erratic shifting was caused simply by low fluid. The underneath was a little wet so there may be a slow leak.. I’ll have to fix that if this is the cause. Lets hope that this will fix it!

 

[SGT_BlackSmoke]

That was not the problem! Drops out of gear and says to shift to neutral once it gets hot. No clue here.

 

[Ron Nielson]

You might try just removing the connector from the TCM, cleaning the pins on both sides with Caig Deoxit, and reapply the connector. Might not work, but again, it MIGHT.