2021 5.3l with 8speed hard shift

Chris Palfenier · May 17, 2021

Just wondering if this is a common problem or if there's a recall for this? When I start truck for the first time of the day I have a hard shift from 1st-2nd consistently. Only occurs first time i start it that day and runs smooth afterwards. Its like it gets stuck in that gear then sends me back into the seat when it finally engages next gear.

Evinruder · May 17, 2021

I am glad I’m not alone. My truck does that too. It only happens when the truck is cold. It shifts sloooooowly into D from R, then stutters from first to send and shifts super hard. I heard the issue was the type of fluid and the dealer was supposed to drain and flush the transmission and torque converter with different fluid. My dealer refused.

BlancoSilverado · May 17, 2021

Ya, that wont go away, i did have some fun and went though the modes and found it doesn't do it in tow/haul mode, might be a pressure issue, from what i understand, the line pressure increases when going into tow/haul mode and it will hold higher RPMs. it could also be something that we have no clue about. i haven't done a full flush with the new fluid but i know i have around 7 quarts of the new fluid.

2016 Sierra Owner · May 20, 2021

On 5/16/2021 at 9:08 PM, Chris Palfenier said:

Just wondering if this is a common problem or if there's a recall for this? When I start truck for the first time of the day I have a hard shift from 1st-2nd consistently. Only occurs first time i start it that day and runs smooth afterwards. Its like it gets stuck in that gear then sends me back into the seat when it finally engages next gear.

Welcome to the 8 Speed Transmission ownership blues. Your truck should have the new fluid from the factory since it was changed last year to include all new trucks produced. The problem you are having is an issue of the 8 speed and has since GM started using them in 2017.

Chris Palfenier · May 25, 2021

Well this is disappointing! Had I felt it from the start would have left it on lot! They went and filled truck with gas day i was going to take it so issue wasn't there. I didnt drive it for another week after getting it home. Thought the next few starts were a fluke but dealership is saying gm is considering this normal for this transmission. They will look at it they said but likely won't do anything. Will try the tow/haul mode tomorrow morning.

bigdoug42 · May 29, 2021

On 5/16/2021 at 10:08 PM, Evinruder said:

I am glad I’m not alone. My truck does that too. It only happens when the truck is cold. It shifts sloooooowly into D from R, then stutters from first to send and shifts super hard. I heard the issue was the type of fluid and the dealer was supposed to drain and flush the transmission and torque converter with different fluid. My dealer refused.

Go to another dealer, the condition has to be diagnosed while driving with a transmission that is warmed up. Gm has a TSC on the condition. I had the flush and refill done on mine and it shifts very smooth now. Print out the TSC and show it to the service writer, it should get you at least looked at.

Hope this helps.