Who likes their 8 Speed?

Lgetz · July 20, 2016

My truck developed the vibration and it would shutter while shifting so I took it in to my dealer for the oil change and went over it with them a few weeks ago. They tested the torque converter slippage and said that was my problem. They replaced it just before a big trip from FL to MI and just over 3000 miles. It's like driving a completely new truck. There is Zero vibration and the little bit of clunking (usually only when shifting into drive from park) I had is gone.

On another note. I got 21.1 mpg over all which included driving 75-77 on the interstate, letting my bro-in-law pull his boat some in NC and around the towns in our destinations.

My truck also developed the shudder recently. Have taken it in twice to the dealer. First time they did an update which lessened thr problem for a day. Shudder came back with a vengeance and after a trip up to Austin I left it at the dealer a couple of days ago. Got a call this morning that a new torque convertor was received and truck may be ready later today.

flasch192 · July 21, 2016

Took my gmc in last week for the 3rd time, dealer finally called gm tech service, they found the front pump leaking , gm is sending a new trans and converter ...

My symptoms where a very slow 2nd too 3rd upshift harsh down shift from 2 too 1 and surgeing when switching from v8 too v4,5500 miles .....

Edited July 21, 2016 by flasch192

mookdoc6 · July 21, 2016

Took my gmc in last week for the 3rd time, dealer finally called gm tech service, they found the front pump leaking , gm is sending a new trans and converter ...

My symptoms where a very slow 2nd too 3rd upshift harsh down shift from 2 too 1 and surgeing when switching from v8 too v4,5500 miles .....

What was your build date if you don't sharing?

flasch192 · July 21, 2016

I'll have too grab when I get it back ...

Lgetz · August 2, 2016

Update to my issue. The torque convertor on my truck was replaced and truck was given back on the 20th of last month. Have only put on about 300 miles or so since but there is still a slight shudder under moderate acceleration between 1400- 1700 rpms. It is apparent because the steering wheel vibrates and this never happened before I started having problems.

jrodriguez_20807 · August 2, 2016

I have about 4000 miles on mine 6.2 with 8 speed and man it is smooth as silk.. I really like it compared to my 2012 5.3 6 speed...

wetcoaster · August 2, 2016

An update on mine. The clunking is still there and the shop foreman said just keep complaining to GM Customer Care because there's nothing he can do without a software update from GM. He doesn't believe it's a mechanical issue at all. i e-mailed GM customer care a couple of times and they seem to be ignoring my e-mails now. This is a really disappointing situation and now I'm going to have to look for different avenues to get this solved because I'm not happy with the way it drives. It didn't drive like this during the test drive and I expect it not to now. I first logged my complaint at the dealership at around 3000km's and I'm at 11,000km's now and still have the problem.

Does anyone know of any other ways to get this fixed? Lawyers?

Edited August 2, 2016 by wetcoaster

JacobC1983 · August 3, 2016

Honestly, I don't know how to help you but I can tell you what happened with mine. Most of it was through the dealer, I never called GM customer care once. My dealer called TAC (if that is how you spell it) multiple times trying to get mine taken care of for me. From several relearns to a new torque converter to them sending out a field service engineer, then finally to getting me GM trade assistance. I just called my service guy about once a week for several months giving him my updates on how my truck acted. I had the 6.2L with 8 speed (2015 model year)

I never got mad at him, was always kind and he was more than willing to help me. Never threatened lawyers (and my wife is a lawyer, it would have been easy)... Finally I got to the point where I said I understand there is a problem and you can't fix something they won't let you fix or tell you how to fix, let's just get me into another truck with GM trade assistance - and they did. It took several weeks but it all worked out. My new 2016 6 speed drives perfectly after 1500 miles.

I gave them my 2015 with 9000 miles, with the GM trade assistance I got a brand new 2016 with an MSRP within $200 of my old one, and it cost me $199. Well worth the trouble.

The service manager and the sales manager both told me (in private) that the squeeky wheel gets the grease, just keep calling and good things will happen.

Edited August 3, 2016 by JacobC1983

CptMcSaug · August 3, 2016

I have developed a shutter now at 22k miles. Waiting on the dealer to get a new converter in and see if its helps...

wetcoaster · August 3, 2016

Honestly, I don't know how to help you but I can tell you what happened with mine. Most of it was through the dealer, I never called GM customer care once. My dealer called TAC (if that is how you spell it) multiple times trying to get mine taken care of for me. From several relearns to a new torque converter to them sending out a field service engineer, then finally to getting me GM trade assistance. I just called my service guy about once a week for several months giving him my updates on how my truck acted. I had the 6.2L with 8 speed (2015 model year)

I never got mad at him, was always kind and he was more than willing to help me. Never threatened lawyers (and my wife is a lawyer, it would have been easy)... Finally I got to the point where I said I understand there is a problem and you can't fix something they won't let you fix or tell you how to fix, let's just get me into another truck with GM trade assistance - and they did. It took several weeks but it all worked out. My new 2016 6 speed drives perfectly after 1500 miles.

I gave them my 2015 with 9000 miles, with the GM trade assistance I got a brand new 2016 with an MSRP within $200 of my old one, and it cost me $199. Well worth the trouble.

The service manager and the sales manager both told me (in private) that the squeeky wheel gets the grease, just keep calling and good things will happen.

Thanks for the insight. I've never got mad at anyone. I've just exhausted the service department's abilities. The dealer I get it serviced at is not the same as the dealer I purchased it at because of geographical convenience.

I'm also not really interested in downgrading from the 6.2L I love. towing a travel trailer was fun with the power of the 6.2. The shifting drives me nuts. Particularly every single morning down the hill I live on where it feels like I'm being rear ended on my way to work.

Is there actually a 2016 8 speed that has no clunks or is it just the way it's programmed?

JacobC1983 · August 3, 2016

I have read that the later 2016s with the 8 speed get an updated transmission with the new torque converter and different valves. It seems that the later manufactured 8 speeds don't have as many issues, but they haven't been out as long, obviously. Your best chance would be a new transmission. They put the new torque converter in mine when I had it, and while it did clean up shifting, it didn't alleviate the large clunks and jolts forward when downshifting in parking lots. The worst part was coming to a stop at work in the parking garage when somebody jumps out in front of you... and the truck lunges forward towards them.

Snoringbear · August 3, 2016

I have read that the later 2016s with the 8 speed get an updated transmission with the new torque converter and different valves. It seems that the later manufactured 8 speeds don't have as many issues, but they haven't been out as long, obviously. Your best chance would be a new transmission. They put the new torque converter in mine when I had it, and while it did clean up shifting, it didn't alleviate the large clunks and jolts forward when downshifting in parking lots. The worst part was coming to a stop at work in the parking garage when somebody jumps out in front of you... and the truck lunges forward towards them.

I thinking one thing GM should do, being that the 6.2L has 420 hp/460 ft-lb's, is to design the 8 Spd tranny so that 1st gear is blocked out unless in tow mode. The current up-shift time from 1st to 2nd gear under normal driving is just a matter of a second or two which sometimes gives the sudden jolt or hit when making the up-shift. Just a thought

mookdoc6 · August 3, 2016

once it's put on incline or large grade the 8speed is almost perfect! But, yeah I hear ya going 5mph around that first corner after pulling out of the driveway can be felt.

After driving mine for 7,000+ miles it really has settled down and I think it's a fantastic setup!

Badass69 · August 3, 2016

I dunno... mine was too easy. It was clunking more around town and delayed bad shifting out of park. Told the local dealer service guys about and they booked it in and said it sounded like it needed the stator TSB. They had it one day, tested it and then gave it back while they ordered parts. Once everything came in ( took about 3 weeks) they had it 2 days and it's been pretty good. Time will tell. I am approaching 25000 miles on my truck.

Sent from my SM-G900W8 using Tapatalk

Edited August 3, 2016 by 1994Vmax

akkrezz · August 3, 2016

I think it's funny how people think GM trucks are the only ones with issues.. Switching brands isn't always the answer. I can see how people get feed up with GM and switch because of that, but just be careful cause fords and dodges both have their own issues, and similar ones too.

But in regards to the post, my 2015 6.2L 8spd shifts pretty well. When I first got it and it was learning my driving it was definitely annoying and I actually had the dealership reset the tranny once. But after that it's been fine. There are hard downshifts here and there, mostly random, but nothing that shakes the whole vehicle. I also tuned my ECM with the Diablo intune i2 and it made the whole truck drive so much smoother. Can't wait till Diablo offers support for the TCM of the 8spds