2015 Truck 6.2 L Engine, 8L90E Transmission troubles, problems, fixes

pm26 · March 2, 2016

Hello

Thinking about purchasing a new GM truck. I am wondering if anyone is having any problems with their new 1/2 ton trucks. Is GM having any problems with the 6.2 Liter Eco Tec 3 engine or still having some troubles with the new 8L90E Transmission. Other troubles and their solutions would be intresting too.

It would be nice to learn in advance what to expect, will it be a wonderful smooth ride. Should I expect a few fixable bumps along the way or am I entering a nightmare ride.

Thanks in advance for your input.

Success stories are certainly welcomed for a well rounded view.

Chances are, it will be "a wonderful smooth ride" for about 3000 miles, by which time the sloppy tolerances and shoddy assembly of various moving parts will rear their ugly head. Then it is time to trade the truck in for a new one.

SierraMyst · March 2, 2016

UPDATE:

Got my truck back yesterday with the new transmission they promised, It has performed without a flaw...no hard shifting or any clunking...I'm keeping my fingers crossed that all stays that way.....I guess I will see if it holds up after a couple hundred miles...wish me luck!

Please keep us updated.

Jtodd · March 4, 2016

UPDATE:

After recieving my truck back on Monday, with the new transmission as of yesterday afternoon it began to hard shift and make a banging noise when I accelerate and decelerate. Seems like the more I drive it the worse it's getting! I have a case with GMC just called and left numerous messages...TELLING THEM I WANT OUT OF THIS TRUCK!!!it has cost me nothing but time and money

pm26 · March 4, 2016

UPDATE:

After recieving my truck back on Monday, with the new transmission as of yesterday afternoon it began to hard shift and make a banging noise when I accelerate and decelerate. Seems like the more I drive it the worse it's getting! I have a case with GMC just called and left numerous messages...TELLING THEM I WANT OUT OF THIS TRUCK!!!it has cost me nothing but time and money

That's really frustrating. Especially for a truck with a nice engine like the 6.2, and nice interior trim on top of that.

CounterMeasure · March 6, 2016

UPDATE:

After recieving my truck back on Monday, with the new transmission as of yesterday afternoon it began to hard shift and make a banging noise when I accelerate and decelerate. Seems like the more I drive it the worse it's getting! I have a case with GMC just called and left numerous messages...TELLING THEM I WANT OUT OF THIS TRUCK!!!it has cost me nothing but time and money

I've had two transmissions in my 6.2, along with many "relearn procedures", so I really feel for you. In case it helps, what I noticed for each of those cases is for the first few miles, the transmission was really nice and smooth. Then after that it got really bangy and clunky with lots of harsh shifting. Especially when cold. Then a few hundred miles later it settled in a bit, but it never gets back to that original smoothness.

What I've been told by those "in the know" is that's part of the programming to figure out the shift pressures. The transmission data tables have specific shift times, depending on RPM, torque, temp and so forth. So the transmission has to figure out the shift pressures needed to hit those times. And the only way it can figure them out is to try different pressures and record if it hits those times. Recently, I've personally seen the data tables in question, and what sucks is there are A LOT of values in the tables for the various factors. So it can take a while for the transmission figure out the pressures, because you have to take it through the various driving conditions for each of those points.

Long story short, I'd bet that if you give it more miles, it will settle down. But I am totally with you that it really sucks in the mean time. There was a period of time in all that mess that I also wanted out of my truck and back into my Tundra. Sometimes I still do, but not worth the trade loss and hassle at this point. So I've decided it will be the last GM product I will own, or at least for a very long time, and I try to dissuade friends and family away from a GM product by telling them all the issues I've had and how they've treated me.

Jtodd · March 6, 2016

I've had two transmissions in my 6.2, along with many "relearn procedures", so I really feel for you. In case it helps, what I noticed for each of those cases is for the first few miles, the transmission was really nice and smooth. Then after that it got really bangy and clunky with lots of harsh shifting. Especially when cold. Then a few hundred miles later it settled in a bit, but it never gets back to that original smoothness.

What I've been told by those "in the know" is that's part of the programming to figure out the shift pressures. The transmission data tables have specific shift times, depending on RPM, torque, temp and so forth. So the transmission has to figure out the shift pressures needed to hit those times. And the only way it can figure them out is to try different pressures and record if it hits those times. Recently, I've personally seen the data tables in question, and what sucks is there are A LOT of values in the tables for the various factors. So it can take a while for the transmission figure out the pressures, because you have to take it through the various driving conditions for each of those points.

Long story short, I'd bet that if you give it more miles, it will settle down. But I am totally with you that it really sucks in the mean time. There was a period of time in all that mess that I also wanted out of my truck and back into my Tundra. Sometimes I still do, but not worth the trade loss and hassle at this point. So I've decided it will be the last GM product I will own, or at least for a very long time, and I try to dissuade friends and family away from a GM product by telling them all the issues I've had and how they've treated me.

Jtodd · March 6, 2016

Thanks for the info!! This has been the most depressing vehicle I have ever owned, "What a nightmare"! I too will never have anything good to say about owning a GMC!

txmuder · March 7, 2016

Jim,

Did the updates correct the shift from park to drive and did you have a delay or clunking before the updates?

If you could post the procedure numbers that would help a lot of folks on here.

Yes JB it did but now after 4 weeks almost its still very smooth and no more issues as of today that is.

Not sure of the procedure number but I will dig up the warranty ticket to see if it has one, I remember the service manager/Adviser told me that it required 3 different upgrades to the TCM (transmission control module)

Jtodd · March 17, 2016

Back at the dealership after a new transmission..took it in 2 days ago...haven't heard anything yet....this will be the 4th time since November....??

Wnc66 · March 23, 2016

I'm also dealing with this matter! What a crock! Love the motor but the transmissions are junk! Dealer and Chevrolet giving me the Bs stories! Last Chevrolet ever! I work for a major supplier for GM, and all I can say to my coworkers is how disappointed I am with this truck! They listen!

Jtodd · March 24, 2016

I know what you mean!!its all a crock..just received my truck back 3 days ago and as of yesterday it's back to hard shifts and clunking.Been trying to get ahold of the GMC REP handling my case but she is out on Easter Vacation.

GMCustomerService · March 25, 2016

I know what you mean!!its all a crock..just received my truck back 3 days ago and as of yesterday it's back to hard shifts and clunking.Been trying to get ahold of the GMC REP handling my case but she is out on Easter Vacation.

Good Afternoon Jtodd,

I would certainly like to look into your case further and assist with any questions you have regarding your truck. Please feel free to send us a private message with any questions you have. Thank you and we look forward to hearing from you.

Anisha T.

GM Customer Service

bmc350 · March 25, 2016

Thank you all for documenting your issues with your trucks. My truck is a 2015 Sierra w/6.2. Has been having minor shift issues for a while and they started getting progressively worse. At the point now that I have to take it in, as the service 4WD recently started showing. Beside the very hard shifts, I'm also having transfer case issues and recently found out my truck has been stuck in 4WD Hi and will not come out of it. This thread and a few others gave me some information for when I take it into service. Good luck with all your trucks...

Jtodd · March 25, 2016

Good Afternoon Jtodd,

I would certainly like to look into your case further and assist with any questions you have regarding your truck. Please feel free to send us a private message with any questions you have. Thank you and we look forward to hearing from you.

Anisha T.

GM Customer Service