My own 8 speed problems & resolution

brendan4862 · April 21, 2016

what does GM call an "updated transmission"? A transmission that was actually assembled by people who have some idea what they are doing (vs totally clueless)?

I was told by the service manager the updated transmissions have a different torque converter and different internal valves/solenoids.

brendan4862 · April 21, 2016

FINAL update:

My dealership offered me a decent amount of money to simply buy it back through them without GM involvement. I took that offer and am happy it's over with. I took the easy way out. Should I have taken it further? Probably, but I don't have that much free time on my hands.

Once again, I wish all of you luck with this. I'm hoping there is resolution somewhere in the near future.

JacobC1983 · April 28, 2016

I am still waiting for the field service engineer to show up here...

what did you end up buying instead?

1KWK-BRD · April 29, 2016

Well back again. My service dept. replaced a control module for the 4 wheel drive and manipulated the computer for over 2 weeks. My truck is better than before but the tach still jumps around especially going up hill and once you get to the top the tach jumps way up there.

I'm going to drive it awhile the wife and I are going to be towing with it Sat. I want too see how it acts with a 30 ft. boat behind it. Is it right no I don't think so. Just really sucks I love the truck. Hope some of u guys are having better luck. Will update after the boat ride.

brendan4862 · April 29, 2016

I am still waiting for the field service engineer to show up here...

what did you end up buying instead?

Nothing. I didn't want another Chevrolet truck so I walked away from buying any vehicle. GM corporate did not like that one bit.

JacobC1983 · April 29, 2016

Did you have a second car already or something? When I finally trade mine in I am wondering if I am going to jump ship as well.

brendan4862 · April 30, 2016

Did you have a second car already or something? When I finally trade mine in I am wondering if I am going to jump ship as well.

I do have some other cars, which make it easier. I've always had used cars and that truck was the first ever I bought new. I wanted a brand new truck for every day worry free driving and it didn't happen. I was so sick of always fixing things here or there on weekends.

So I'm back to my other 50k mile plus cars.

2006 GTO, 1966 GTO convertible, 2010 CTS, 2012 SRX, 1969 Camaro SS, 2004 GMC 2500HD are the current vehicles in the stable between me and the old lady.

Edited April 30, 2016 by brendan4862

wetcoaster · May 13, 2016

I'm taking my truck in for the second time with 8 speed transmission issues. I took it in about 2 weeks ago and the performed all of the TSB updates for the programming and it shifted worse than ever. Clunking on upshifts like it was a 1980 Camaro with a stage 25,839,874,329,876,443 shift kit.

The last straw which made me call in for a second service appointment was me starting from a stop on a 3% decline at less than 5mph it felt like I was rear ended hard. I looked back behind me and there was no car. I'm guessing there was no pre-load on the pinion gear and it was between shifts when I started to roll forward and then locked up with some backlash. This is strike #2. If I get it back next Tuesday and I have one more tranny fart, I'm going to be looking to do the same as the OP.

JacobC1983 · May 13, 2016

Mine just had a field service engineer look the truck over. I took it in on Tuesday and still haven't gotten the truck back. The service department said he took a bunch of data with him and asked for more data when he returned home. Still no idea what's going on with it.

4emeryj44 · May 25, 2016

This whole thread has been very disheartening to read. I just bought my absolute DREAM GMC Sierra for Christmas. I am in the U.S. Army, have deployed to Afghanistan twice, and finally wanted to buy a truck that was going to be my dream, something I felt I earned and deserved to buy myself. This truck represents more to me than just transportation, it represents America (haha sorry) but seriously it does for me. It was a present to myself for the things I've done and sacrificed for. I hate to throw the military thing out there, but it's how I feel about my truck. I'm a very humble person. My point is, these trucks aren't just trucks to us "truck guys and gals" they are a second home, an office, your personal space, a representation of who you are, your lifestyle.

The fact of the matter with what I just stated, to receive an answer of "it's normal" or "deal with it". That doesn't fly with my, I've "dealt with it" more than anyone working at GM can understand, I've endured "the suck" and dealt with shitty situations. This is NOT one of those situations where any of us should have to deal with. I am having a downshifting clunk issue with my truck as well and I'm posting the link to my thread below.

The only thing I can think to do, obviously for us that aren't resolved is to come together and share our experiences just like we are doing on the forum. I hope I can resolve my issue, but it seems as though the bad 8 speeds are never going to be fixed. It's not ALL the trucks, which I know someone mentioned. My buddy bought the exact same truck as me 1 month after I did and his truck is perfectly fine. I'm also wondering if we all have case #'s, that maybe we can make a combined centralized thread with all our case #'s or something to that affect that we can refer GM or our dealerships to that will show a mass problem that is out there. IDK could be just saying stuff way out of my lane. Anyways, I hope to get my issues resolved as I love my truck, and for those of you that have issues as well I hope the best to you all as well.

http://www.gm-trucks.com/forums/topic/187821-2016-gmc-sierra-1500-cc-z71-8l90-2nd-to-1st-downshift-issues/?do=findComment&comment=1815234

JacobC1983 · June 26, 2016

Well I have an update..

My truck is being traded with GM assistance... I went with the 5.3 and 6 speed this time. I will be losing my 6.2L and 8 speed. I am going to miss the power. My dealer looked for trucks with the 6.2 and 8 speed and the surrounding dealers wouldn't trade them for a truck on their lot since they didn't have a 6.2 to trade for a 6.2. But, I get a truck in return with more options so I guess that's a plus. Honestly, I am glad the new truck doesn't have the 8 speed because mine was awful. I am just going to miss the 6.2L.

I am glad your issues were resolved!

Edited June 26, 2016 by JacobC1983

IPB · August 3, 2016

I hate to bump an old thread, but I'm going to!

How long did this process take? My 15 with 6.2 and 8spd has 20k on it, I've had the torque converter replaced, I've had the tranny replaced, and its still horrible. I essentially have a $60k truck that I hate, so I drive my 03 project wrangler around! The grill was replaced at around 5k miles as it was falling apart, and now my dash is coming apart. This is the worst purchase of my car buying life and I've bought many. Never should have traded my 09 2500HD diesel for this POS.

Between driving the 45 minutes it takes to get to the dealer and the amount of times of been I'd love to wash my hands of this damn thing.

JacobC1983 · August 4, 2016

The process to get GM trade assistance through my dealer took about a month after all the failed service and torque converter replacement.

flasch192 · August 6, 2016

well guys I hope I'm not speaking too soon but I have about 600 miles on my new trans and convertor and all seems well, had 1 hard downshift at 75 miles , had too look in my mirror thought I got rear ended lol , but other then that its been spot on , the switch from 8 too 4 is omost seamless and when you punch the gas it hauls ass like it should ...............

Dndodd · August 10, 2016

My problems seem to occur at very low rpm 1k-1.5k SPEEDS 30-45. Hesitation, some what jerky at times, like it is hunting for the right gear but can't seem to find it. The Tach also seems to flutter with a constant foot on the gas. And occasional clunk or hard shift.

Anybody else having similar problems?

One time it even locked into a gear I was doing 4,000 RPM at 60-65. Had to pull over turn it off, restart and that problem has not reoccurred.