3500GMC
What T F, over
Truck in signature. It has an annoying 4-3 downshift under load. This is with shifter in OD(4)... Rolling along, either with cruise set or with my foot doing the work, doesn't matter, in 4th gear lockup, start asending a grade, the TC will unlock then the trans will shift into 3rd no problem... Problem is: This is where it stays 'no matter what' until I either:
a) shift into neutral while rolling, shut down engine, restart, shift back into 4th and go.. The trans is now in 4th lockup like it should be. Or.
b) get to the next stop and shut off key/engine and restart. Same same.
Other: I can duplicate this 10 out of 10 if I just barely ease into the throttle (cruise also), but if I use a little more sudden pedal movement, maybe a 1/4 inch, it won't downshift- just pulls until speed is reached.
I suspect a noisy TPS... or.. ??? Trans computer is getting a headache?
a) shift into neutral while rolling, shut down engine, restart, shift back into 4th and go.. The trans is now in 4th lockup like it should be. Or.
b) get to the next stop and shut off key/engine and restart. Same same.
Other: I can duplicate this 10 out of 10 if I just barely ease into the throttle (cruise also), but if I use a little more sudden pedal movement, maybe a 1/4 inch, it won't downshift- just pulls until speed is reached.
I suspect a noisy TPS... or.. ??? Trans computer is getting a headache?
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