Rough shift in 2017 8 speed automatic

[Poffdaddy]

I have a 2017 silverado with 8 speed and 6.2 v8. I have a rough shift from 1-2 at parking lot speeds. It clunks shifting down sometimes as well but not usually as bad. It now has 3500 miles. I have already taken it to the dealership twice. They performed the quick learn tsb after service manager verified rough shift. The sound does not seem like it could be good for transmission. I have read about a lot of people having issues. After quick learn it seemed better but now it seems to be getting worse again. I hoped after the 3rd year of transmission being out maybe it would be fixed. Have tried tow/haul mode and it doesn't do it as often. Does anyone have enough miles on this similar truck that issue went away and transmission did finally "learn" how to not destroy itself? If am going to lemon law it I am going to soon.

[relsoc]

What you're experiencing is due to the way the trans control module is programmed. The trans is solid and until gm engineering figures out better programming they will continue to shift that way. Mine does the same thing.

[scott19677]

Try driving in M7. This will disable V4 mode and really helps driving in town. Then just switch up to 8th at highway speeds. Short of a custom tune....? Well thank the GM engineers. Not to rub it in but my Blackbear tuned 6 speed is perfect.

[alejalva]

I had the same problems and even got GM to replace the transmission. A few months later it started doing it again with the new transmission. I traded it in for another non-GM vehicle. It's a know problem that needs a software fix. I just got tired of dealing with it. I'm relieved to not have this problem anymore. My truck had 29k when I traded it in.

 

 

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[amxguy1970]

Lemon law for a rough shift, wow. I might have seen everything now. Let us know how that works for you. What is next, someone going to lemon law it because of the V4 to V8 squeak?

 

Tyler

[jrodriguez_20807]

I have 15000 miles on mine and it started acting up when I swapped my rims from the 20"s to 22"s but they did a quick relearn and it worked fine after that.

[Poffdaddy]

At relsoc. How many miles does yours have?

[396_425]

My 2017 Sierra, max tow and 6.2 has the 1-2 upshift clunk at very low speeds with 1500 miles. Any depression of the gas pedal eliminates the clunk.

[Sir Dan]

At 7000 mi. my 8 speed has a delayed upshift from 1-2 but only when cold. Then there is a harsh downshift sometimes from 2-1 or 3-1 as i understand this transmission sometimes skips 2nd gear on downshift by design. Since I disabled the v-4 mode with a tuner it has been much better but still acts up now and then. Overall very dis-pleased with this truck due to chevy shake and crappy shifting. Engine seems great though, powerful and smooth.

[No F-bdy Bs]

I have been leary of a 6.2 truck due tk the known trans issues, and am afraid the 8spd will be looked back on as a bastard, with the new 10spd in the future.

[Crstfr]

join the club!.. my 5.3 8speed does the same clunk in 1-2 upshift and 2-1 downshift... ... when i had my oil changed i told them to look at it.. they ran tests and said there's no error codes on the tranny.. well in my satifaction survey , i noted at the end i took it in for that.. and its still doing it.. sure it might not be throwing a code, but for a 55k truck, i shouldn't be able to feel/hear those shifts like i do.. we'll see what they say.

[Donstar]

At 7000 mi. my 8 speed has a delayed upshift from 1-2 but only when cold. Then there is a harsh downshift sometimes from 2-1 or 3-1 as i understand this transmission sometimes skips 2nd gear on downshift by design. Since I disabled the v-4 mode with a tuner it has been much better but still acts up now and then. Overall very dis-pleased with this truck due to chevy shake and crappy shifting. Engine seems great though, powerful and smooth.

At 7,000 miles I would not accept driving an LTZ with a "chevy shake and crappy shifting". What steps has your dealer taken to resolve your concerns? I imagine the "tune" may impact service to your transmission but the shake should be resolved (unless you have done some suspension modifications). I have found GM reasonable to deal with when I have a complaint.

[Sir Dan]

Well, there is a huge long thread on here somewhere that can attest to dealers not resolving the shake. I've been to 2 different ones. No help and can't replicate tranny issue. Go figure.

[Poffdaddy]

At No F-bdy Bs. I am concerned about the same issue that the 8 speed transmission was a stepping stone to the 10 speed and nothing will ever get done about it. I think it is short lived sp engineering focus is nor on fixing it and until an aftermarket tune makes it better, which of course voids warranty we will be stuck with crappy shifting transmissions. It's disappointing because everything else about the pickup is great.

[mookdoc6]

At No F-bdy Bs. I am concerned about the same issue that the 8 speed transmission was a stepping stone to the 10 speed and nothing will ever get done about it. I think it is short lived sp engineering focus is nor on fixing it and until an aftermarket tune makes it better, which of course voids warranty we will be stuck with crappy shifting transmissions. It's disappointing because everything else about the pickup is great.

I hear what your saying....I am 23,000 miles and it's pretty dang smooth now! What a bastard up to 10,000 miles it seemed! I don't care what GM says or anybody on this forum..........Once you ascertain that the Tranny is solid stick with it and get a BlackBear Tune! I had to fight Goliath to Pay for my Tranny Flush/Fill Long story..........Get the Fast Learn.............Get the papers that specifically explain how to drive your truck for 5 miles on FLAT PLANE SURFACE AT EXACT INSTRUCTIONS! Look, you will do this out in the country at 11-12PM on your day off like I have because no TECH EVEN KNOWS THAT IS WHAT MUST BE DONE TO DIAL THE MOHTER F'R IN! PAY 300.00 dollars or demand Dealer to replace all TRANNY FLUID/Filter and Relfash.......Tell them to F OFF at that point and spend your night in country driving/dialing it in..................Put it this way I am shocked how smooth this Tranny shifts now? I can only feel 1-2 and the rest I can't even pick out only with the tach......