Transmission Went Out - 2016 8-Speed

Darcy13 · April 17, 2016

(Continuation of reply in Transmission Issues/Problems)

My 2016 LTZ Crew Cab Z71 with an 8-speed & 3.42 rear end was doing its own version of the clunky marginal shifting described in several other threads on this forum. I never found the shift behavior of the transmission unbearable, but there were times where it would get extremely confused as to what it should be doing from first to second gear. It was something I was planning on bringing up at my first oil change, but it turns out that was not necessary; my truck decided it was done shifting at 4100 miles on the odo.

I pulled up behind a car waiting in the left turn lane of a busy intersection. After a couple seconds, arrow turns green, car in front of me starts going, I hit the gas, and the engine winds up like I'm in neutral, and I'm not going anywhere. I shift to park, back to drive, into reverse, into AWD, no dice. Having heard no telltale clunk or pop, I figure it's an electrical issue, so I pull the negative battery cable off the post, but no luck with the hard reset. I end up having to get my truck towed to the dealership.

Service Coordinator calls me a couple days later with what he says is good news. Turns out that "good news" is that they are going to put a brand new transmission on my truck. I asked if the pan had any large filings or chunks of metal, and it did not, nor did the input shaft show any signs of damage. According to the technician, no apparent sign of mechanical failure. GM wants the tranny back for inspection, so now I'm going to have to wait another week for them to get a transmission in from Detroit.

Just thought I'd share that story. Hopefully this doesn't happen to any of y'all. I'm not a big fan of having to explain to my coworkers and buddies the reason why I'm driving around a Chevy Equinox.

pm26 · April 17, 2016

Going from 8 speed to zero speed in 4k miles is indicative of completely failed quality control.

SILVER SLED · April 17, 2016

I think the problem is more to do with hurrying a product to market, like the 8 spd. I've heard about the upcoming 10 speed 4-5 years ago. All of the sudden there is an 8 speed in trucks and corvettes. It seems that GM was trying to keep up with others and rushed a trans to production. Fear not though. The 10 speed will be here soon, and at least has been in development for a while and will hopefully have the bugs worked out BEFORE it goes to production.

CounterMeasure · April 18, 2016

I think the problem is more to do with hurrying a product to market, like the 8 spd. I've heard about the upcoming 10 speed 4-5 years ago. All of the sudden there is an 8 speed in trucks and corvettes. It seems that GM was trying to keep up with others and rushed a trans to production. Fear not though. The 10 speed will be here soon, and at least has been in development for a while and will hopefully have the bugs worked out BEFORE it goes to production.

Even worse is the fact that they developed the 8L90 transmission during their bailout period. GM filed for the patent on the 8L90 in 2009.

When your company is in trouble, the first areas you start cutting are R&D. And your products usually show it.

fondupot · April 18, 2016

GM just need to jump on the ZF bandwagon and start outsourcing their transmissions. The 8 speed trans in my Dad's ram is outstanding. Smooth, quick and does not hesitate.

I wonder if someone will make an adapter kit and custom program one someday.....would be nice.

tnchevy · April 18, 2016

Transmissions do go out and they seem to do it early on if there is a problem with it. In all the company trucks I have had and the guys I work with have had, we have had a few new trucks of different brands where the trans went belly up within the first 5k miles.

CounterMeasure · April 19, 2016

GM just need to jump on the ZF bandwagon and start outsourcing their transmissions. The 8 speed trans in my Dad's ram is outstanding. Smooth, quick and does not hesitate.

I wonder if someone will make an adapter kit and custom program one someday.....would be nice.

Funny thing is the 8L90 is basically based off the ZF 8HP.

http://www.thetruthaboutcars.com/2014/04/saturation-dive-the-gm-8l90-transmission/

fondupot · April 19, 2016

Funny thing is the 8L90 is basically based off the ZF 8HP.

http://www.thetruthaboutcars.com/2014/04/saturation-dive-the-gm-8l90-transmission/

So you're saying we can swap the ZF in? Lol

Rkaroll953 · April 19, 2016

ask if they will swap in an old turbo 400! That would go another 150k no problem! lol

Rock1500 · April 19, 2016

I think the problem is more to do with hurrying a product to market, like the 8 spd. I've heard about the upcoming 10 speed 4-5 years ago. All of the sudden there is an 8 speed in trucks and corvettes. It seems that GM was trying to keep up with others and rushed a trans to production. Fear not though. The 10 speed will be here soon, and at least has been in development for a while and will hopefully have the bugs worked out BEFORE it goes to production.

But if the 10 speed comes out next year then the "market" for 8 will be small in terms of aftermarket parts and replacement. Not a position I'd want to be in. Rather stick with the 6 in that case till the 10 had been around for more than 1 year.

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stereojnky · April 20, 2016

I had to have mine replaced around the 20,000 mile mark. I was just glad that GM stood up to the plate and stood by their warranty.

Don't get me wrong, I was upset that the first new vehicle, that I bought for myself to drive, wasn't living up to my expectations. My dealer made the process seamless and painless. I felt they went above and beyond especially considering that I didn't buy the truck from them.

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pm26 · April 20, 2016

In case you are wondering why GM has reduced the powertrain warranty coverage from 100k to 60k miles on 2016 trucks, it is because they keep installing the same crappy components that do not have expected lifetime much past that 60k miles mark. And GM got burned having to replace too many under the former 100k mile powertrain coverage. So instead of improving the quality of drivetrain components, they are shortening the warranty period.

Why not just adopt a modified version of harborfreight warranty policy? something like 90 days or 6k miles, whichever comes first for the whole truck. This will better indicate the quality built into these vehicles.

Daryl LBZ · April 20, 2016

In case you are wondering why GM has reduced the powertrain warranty coverage from 100k to 60k miles on 2016 trucks, it is because they keep installing crappy components that do not have expected lifetime much past that 60k miles mark. So instead of improving the quality of drivetrain components, they are shortening the warranty period.

Why not just adopt a modified version of harborfreight warranty policy? something like 90 days or 6k miles, whichever comes first for the whole truck. This will better indicate the quality built into these vehicles.

I hate to say it, but this very same thought has crossed my mind a few times.

SILVER SLED · April 20, 2016

But if the 10 speed comes out next year then the "market" for 8 will be small in terms of aftermarket parts and replacement. Not a position I'd want to be in. Rather stick with the 6 in that case till the 10 had been around for more than 1 year.

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I've mentioned that before in another thread. I feel the same way.