Stuck in 1st Gear!

[TBMSport]

Anyone ever have this problem? And yes, for the record, I'm sure it's not 3rd. :grin: It simply refuses to upshift and is giving no MIL.

[ScarabEpic22]

Is it the 6L80E/T43 thats giving you issues? Stock calibration, or have you adjusted shift parameters? If its all stock, then there is probably a comm error between the ECM and the TCM where the ECM is either not feeding the TCM correct data (like RPM or VSS) or the TCM isnt commanding the shift. Have you scanned it while driving to see what the TCM sees?

[TBMSport]

Hey Eric. This is the 6L80 T43 I'm having issues with. I don't have a scanner to monitor as I drive. But the speedo works, tach works, and no MIL. No PRNDL (again) and a transmission stuck in 1st gear!! If I disconnect the TCM from the ECM I'll get an MIL (no ECM/TCM communication DTC) and then only 3rd gear.:bad:

[ScarabEpic22]

Interesting, have you reset the learned shift settings in the TCM? What TCM tune are you running, you probably need to modify the shift tables in EFILive...

[TBMSport]

Great....now to find someone local who can do that! lol :doh2:

[TBMSport]

Getting a U0100 and U0101 code....TCM/ECM loss communication. Anyone know which modules #00 and #02 are? Can module ID numbers be reassigned?

[ScarabEpic22]

The ECM and TCM arent playing nicely, probably because the TB OS is getting what it considers weird data from the TCM. You need to have a local tuner or someone close with EFILive to modify the shift times and params, but honestly if you're getting comm errors it wont matter.

[TBMSport]

Well the thing is it's a "U" code which means it's a history. The light isn't coming back on. So it seems to me that the TCM isn't seeing what it needs to in order to upshift. Either way I need a Tech II or EFILive...which I don't have. For now I think I'll just park the truck until a new idea hits me or I can find someone local with said equipment to look at it.

[ScarabEpic22]

Yea man, sorry but this is sounding like a familiar problem with ECM <-> TCM comms when running a A4 ECM OS and a A6 TCM OS.