Hi ya'll I'm new on here and new to the duramax world. Bought a 09 lmm down in texas when I was visiting family over the holidays. It has 140xxx miles, and is all stock. The problem i'm getting is when I'm at slower speeds (25-40) it seems like it can't find the correct gear. It is not throwing any codes and runs fine on the highway and it did great pulling a Passat tdi back from texas on the trip home. I saw where someone had this problem but cannot re-locate the thread. Any input would be greatly appreciated!!!
Transmission Acting Weird
- Thread starter tyler89wilson
- Start date
This section is fine.
With no codes its hard to tell. Sometimes the Allison can get confused just because of inconsistent driver input.
Need to explain exactly what its doing, and does it actually shift or is it just lazy?
With no codes its hard to tell. Sometimes the Allison can get confused just because of inconsistent driver input.
Need to explain exactly what its doing, and does it actually shift or is it just lazy?
It shifts from 3rd to 4th back to 3rd. like its searching for the correct gear on a consistent throttle. What do you mean by reset the taps? I've been reading a lot trying to learn all about these trucks, so sorry if my knowledge isn't "up to key". FNG here.
:welcome2: Congrats on the purchase of the truck! Hopefully people can help you with the problem.
Sorry, but I have to ask the dumb question of: Are the roads you are driving on at 25-40 mph as stated level? And how constant are you with the pedal? like perfectly steady, or slight variations? GM like to lock and unlock the converter in the second and third gear ranges a lot. Hopefully Mike L will comment when it becomes time to wake up on that side of the country (California)
Sorry, but I have to ask the dumb question of: Are the roads you are driving on at 25-40 mph as stated level? And how constant are you with the pedal? like perfectly steady, or slight variations? GM like to lock and unlock the converter in the second and third gear ranges a lot. Hopefully Mike L will comment when it becomes time to wake up on that side of the country (California)
Some of the roads are not level and some are pretty dang level. Doesn't seem to happen all the time but when it does I start worrying. I think I have a pretty foot but hey, I could be wrong. If its not the converter locking up what do you suggest?
Would a t/c going out cause this or a shift solenoid? It's not throwing any codes. Also would a transgo jr fix this?