Another 8 speed nightmare.

[Whiplashed by GM]

I bought a 2015 Sierra All Terrain with the 6.2 brand new in May of 2015 and now I have ~36,000 miles.  My truck has been re-programmed 5 times, had the transmission flushed and finally a month ago, the local dealer replaced the transmission with a reman.  Now after ~2000 miles I still have whiplash inducing hard downshifts and slipping then slam into gear.  I have contacted a Lemon Law lawyer and am waiting GM's response.  GM wants to attempt to repair the new reman transmission.  I say they've had 6 chances and if a new tranny doesn't fix it, then what will?  

Anyone been down this path with the Lemon Law and how did GM treat you?  I've been a lifetime GM customer with 4 of my last new vehicle purchases being GM products.  

[KARNUT]

My nephew bought a used ford 2 months ago. A very nice fully loaded low mileage truck. I saw him today without the truck,turns out they are having transmission issues too. He says there’s so many failures the dealer told him he may get his truck back for Christmas, parts are on back order. His fathers Ram has 200K miles on it he talk him in to buying a new one so he could drive the old one while he waits.


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[gtbigup01]

Pretty sad. I wish I had joined this forum before I made my purchase, but as an owner of a 2017 Sierra SLT for 3 1/2 months and 10, 827 miles I have the same issue and had the software update done last week. It drove fine for 2 days but now back to the same "Clunk" as I check my rear view to see if I was rear-ended. Damn shame for my first domestic product. I guess you live and you learn. 

[Bobby Hawkins]

My 2017 GMC Duramax feels like the driveline has a quarter turn slack in it in stop and go traffic Especially about 23 mph on light throttle just trying to keep up with traffic Also very noticeable with trailer hooked up Dealer and GM says no problem with vehicle Anyone else notice this

[youn1033]

Does anyone know how long it takes for this transmission to "learn"? Or will it be clunky when I first start it forever?

[JUS1MO]

I don't think anyone has a clue about all these transmission problems or how to fix it. One would think that the Transmission manufacturer would come up with a way to correct this. As the weather is getting colder I find that the problem seem to be getting worse.

 

I wonder if anyone anywhere has one of these 8 speeds that works correctly???

[BigBadSierra]

I'll tell you this right now when the 10 speed that is in the Fords now hit the GM's they will shift like crap even though they shift so well in the Fords.

 

GM programs their transmissions to stay into the highest gear possible for as long as possible.

 

So in normal flat driving they are fine but start dealing with allot of throttle and stop and go they are in the wrong gear half the time so they make harsh shifts.

 

To me this all started around 2005 when GM held on to the 4 speed to long.

 

It's the mind set they use when programming.  That is why everyone who gets a tune has instant better shifting because the remove all of this.

 

My opinion is the extra few mpg are not worth it.

 

Just my 2 cents.

[pm26]

Maybe they should go back to manual transmissions?

[tnchevy]

Or just go back to the 4 speed ones, never had a problem out of my 2002 bu then again I don't have a problem out of my 6 speed in my 2014 either.