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Old 09-01-2021, 01:41 PM   #11
sberlin
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Join Date: Jun 2018
Location: santa cruz
Posts: 33
M.O.C. #22049
Quote:
Originally Posted by twindman View Post
I have a Chevy 2500 with 125,000 miles on it. Up until about 5K miles ago it always shifted into 6th gear when towing at 55mph. Suddenly it now shifts at 67 mph.

Dealer says no codes and that is the way it is! Allison dealer says it is info from the engine that says it isn't putting out enough power to shift at 55.

Sounds to me like some sensor or engine computer part that is sending the wrong info.
Any ideas out there?????????????
My 2015 GMC 3500HD does the same thing as well as "clunking" on the downshift when not towing and coming to a stop. It's not been an issue other than the concern it shouldn't do that. I've seen numerous attorney ads for lemon law suits on Chevy & GMC transmissions. I'm hoping there's nothing to it but but will keep this in mind if I spend $$$$ for repairs.
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