Why is my Allison Transmission not shifting gears?

If the transmission is slipping, repair as needed. Well there you have it: the most likely causes and possible cures for the most common problem plaguing the Allison LCT1000 transmission: inhibited shifts or gear ranges.

Where is the Transmission Control Module on an Allison truck?

Not a connector itself. nsbu, is known to fail especially if you drive the truck in the winter, they are like 60 dollars at the allison shop and if you look through the part numbers they make a protective shield to go over them now A nother thing to check is the tcm (transmission control module) located under hood right by ecm.

Can a bad transmission shift solenoid cause hard shifting?

You may also have intermittent problems with the transmission shift solenoid, which will cause shifting problems. This can cause hard shifting or shiftings at too low or too high RPM, for example.

What kind of differential does a Duramax LB7 have?

At a stock power level, the stock Allison usually does an OK job at transferring the torque from the flywheel to the rear differential, but even a bone stock LB7 can put a hurting on the Allison, so you can only imagine what happens when you turn up the wick or hook up an oversized as many truck owners often do.

Why is my Duramax not shifting out of 2nd gear?

Hey guy my name is john I have a 2001 2500hd duramax and it seems to me it’s not shifting out of either second or 3rd and the shift indicator lights work perfect but staying stuck in either 2 nd or 3rd gear any help would be so greatly appreciated 04LLYDMAX…. Did you ever figure out your problem?

When does range shift inhibited occur in an Allison 6sp?

Range shift inhibited happens in this case when the TCM does not see a rpm drop in engine rpm when it is shifted into drive. This will not set any codes.

What should I do if my Allison won’t shift?

There is another speed sensor at the back of the Allison– same part as the TC sensor.. might put the old one there and test drive it. Be sure you also check for damaged wires. If the display works OK when shifting gears, the NSBU switch may be OK.

Are there any problems with the Allison Transmission?

Allison transmissions are custom-designed for several different industries and provide valuable power and work. However, even these revolutionary pieces of equipment can have problems. Do you know how to identify and deal with an issue that may arise with your Allison transmission?