Inconsistent transmission

TJay74 · October 22, 2014

Got to remember GM has to tune for all of the 50+ year old owners who will gripe about harsh shifting transmissions and that they bought a truck and not a race car.

With that I have bumped up my shift pressures in all of the upshift gears, decreased the shift times by 40% and played around with some other things. So far so good, truck drives a lot better now. under light throttle it almost drives dang near stock until you get into the throttle then it will shift the gears a lot quicker and with more pressure.

pm26 · October 22, 2014

It amazes me how poorly GM tunes thier engines and transmissions. Now that I have tuned my trucks myself with HP tuners, it's amazing how differently my trucks feel. I feel for the op and the others that are complaining, your not crazy. It just makes me laugh that an amateur tuner like myself can fix all the issues I had with driveability in less than a month of trial and error. Yet these engineers with the best equipment and deep pockets can't figure it out.

Yes, the engineers can figure it out, but since GM offers 100k/5 year powertrain warranty, they are forced to tune it for minimum drivetrain loading under most conditions. Maybe it would be better if GM went back to their 3 year/36 months basic warranty only and tuned the trucks right.

juf · October 22, 2014

It's funny you brought up tuning. I recently tuned my truck with the canned tune from DiabloSport. The truck ran amazing.... For about 100 miles then went back to crap. Anyone know why it would do that? For instance, last week I was pulling into traffic going uphill so had to accelerate quickly. The truck went through first gear great, then as soon as it shifted into second it was like the power was cut in half and it was having a hard time accelerating, while traffic was catching up to me fast.

It's frustrating owning this truck because one day I want to sell it because it's driving so poorly and the next day it's fine.

Even just going uphill slowly my truck bogs down.

Of course, dealer always says nothing is wrong if there's no code...

I'm really looking at going to another manufacturer shortly. My '08 Sierra was much more enjoyable to drive, but I'm not sure I can support GM anymore after this truck.

14SLTZ71 · October 24, 2014

It's frustrating owning this truck because one day I want to sell it because it's driving so poorly and the next day it's fine.

I agree 100%.

Silverado-Hareek · October 24, 2014

My truck was in the shop Wednesday for some maintenance and I had another 2014 Silverado as a loaner and the loaner felt much more responsive to the gas pedal and had more "get up and go" than my truck. I wonder if mine is messed up from the learning mode of the transmission because I originally kept the truck under 55 mph for the first 500 miles to help break in the vehicle properly. Of course this constituted city driving with a lot of starts and stops in traffic so there was never any heavy acceleration needed. Now I basically have to put the pedal into the floor to get the truck to f*****g move! It's so sluggish and bogged down all the time. Is there a way I can reset the transmission and put it in a new learning mode? Disconnect a battery cable maybe?

TJay74 · October 25, 2014

Hence why I say drive the vehicle like you are going to drive it. There is absolutely no reason to baby a new vehicle for break in, that day and age was done along time ago.

Only suggestion I would have is to see if you can get the dealer to reset the adaptive learning in the transmission control module and see if that help.

14SLTZ71 · October 25, 2014

My truck was in the shop Wednesday for some maintenance and I had another 2014 Silverado as a loaner and the loaner felt much more responsive to the gas pedal and had more "get up and go" than my truck. I wonder if mine is messed up from the learning mode of the transmission because I originally kept the truck under 55 mph for the first 500 miles to help break in the vehicle properly. Of course this constituted city driving with a lot of starts and stops in traffic so there was never any heavy acceleration needed. Now I basically have to put the pedal into the floor to get the truck to f*****g move! It's so sluggish and bogged down all the time. Is there a way I can reset the transmission and put it in a new learning mode? Disconnect a battery cable maybe?

Have you tried to restart the learning process with a fuse pull for 30 min or you can ask the dealer to reset it.

Here is a link to the post

http://www.gm-trucks.com/forums/topic/159890-how-satisfied-are-you-with-your-2014-gm-truck/?p=1476051

Driver41 · September 2, 2019

I had my 14 chevy 4x4 crew worked on at dealer and the lady actually told me that my drive line was in an awkward position while hauling trailers is what was wrong with mine and another transmission tech told me that it was my tires out of balance. Told me to balance tires and it should clear up. I told him he was a moron and left. I drove 230 miles with a 20 ft car hauler trailer and I got 12 miles per gallon fuel mileage. Prior to the dealership working on transmission same trailer I was getting 16 to 18 mpg. Still haven't been able to get it fixed right.