Who likes their 8 Speed?

AZbound · May 16, 2016

Thank you for this. My 16 just started doing this. Early mornings and after sitting in the parking got for a few hours.

I'll shift reverse, back out of my spot, and shift into drive and it'll take a couple seconds to engage drive.

As always, it doesn't do it all the time and so the dealer will tell me it can't be replicated.

Do you have any of the other pages to the TSD?

Mine does the same thing. 2015 with 35K and several trips to the dealer and absolutely no results. Often when it does engage a very audible clunk can be heard.

Glava2876 · May 16, 2016

As the title states.... My 2015 GMC Sierra with the 6.2L and 8 Speed is at the dealership again with a field service engineer hoping to fix the transmission for the 5th try.

I will trade it in on another GMC Sierra.. and I want the 6.2L again. As you know, this sticks you with the 8 Speed transmission.

So.... Who has a trouble free 8 speed transmission? I have read many threads of problems, but hope to find those without problems to make the final decision: Do I get the 8 speed again in the 2016 model or do I downgrade to the 5.3L and the 6 Speed.

Please put in miles and year of your vehicle with any explanation you want in the thread.

I have 9,600 miles on my 2015 Denali CC 6.2 and I love the 8 speed.

To be fair, I had to bring it in at about 1,500 miles because of a hard 2-1 downshift when coming to a stop.

The dealer did some updates and it has been great since that time.

When you step into it, I love the shift point increase and the nice crisp shifts.

scott.moody.9401 · May 16, 2016

Love mine, 2016 5.3 w/ 8-spd, 7300 miles. The only issue I have is, most of the time, the first shift in the morning is late and firm. It not objectionable but its different and noticeable. It can be minimized with just the right amount of throttle. After that, it's fine

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JacobC1983 · May 16, 2016

Thank you all for the comments. Good info in this thread.

JacobC1983 · May 16, 2016

So nobody has hard downshifts that emanate through the entire drivetrain? Mine happen about once a week or once a tank of gas... There must have been something wrong with mine from the factory.

thetruck454 · May 17, 2016

After my Blackbear tune I like it a lot more now. It's still not perfect, but a lot better for sure

JacobC1983 · May 17, 2016

What problems did it do before the tune, what did the tune fix, and what problems does it still have?

Edited May 17, 2016 by JacobC1983

thetruck454 · May 17, 2016

Some is a preference, for instance during aggressive throttle it used to shift so smooth you didnt feel it, now it hits on each shift. Normal driving is still smooth. On some of the shifts it would have an odd delay like it was slipping, now each shift is purposeful. It does downshift with less throttle now. Things that still anoy me are when it goes through the gears on steady throttle it doesn't shift at the same rpm, like 1-2 @ 4500, 2-3@ 4400, then 3-4. @ 3800, etc. It feels like it shortshifts sometimes. Also it still clunks on decel, which anoys me.

JacobC1983 · May 17, 2016

Ah dang.... the clunk on decel was one of the things I hoped a tune might fix.

thetruck454 · May 17, 2016

Ah dang.... the clunk on decel was one of the things I hoped a tune might fix.

It still might, but I dunno. I'm still on the first iteration tune with Justin. It will be several back and fourths so it may be better. Right now he's working on tuning the blower, I'll focusbon the transmission after the engine is set.

tallspawn · May 17, 2016

I drove all the way home with grade braking off today, wow what a difference on the down shifts. Mines is never horrible but that cleaned up some little weirdness. Dang thing will coast forever now lol.

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JacobC1983 · May 17, 2016

I have 9,600 miles on my 2015 Denali CC 6.2 and I love the 8 speed.

To be fair, I had to bring it in at about 1,500 miles because of a hard 2-1 downshift when coming to a stop.

The dealer did some updates and it has been great since that time.

When you step into it, I love the shift point increase and the nice crisp shifts.

This was one thing I always liked about my truck too. When my foot was in it, the thing was a delight... Nice smooth and quick shifts ... It's when my foot wasn't in it that caused the problems.

Dunc · May 18, 2016

Love it with grade braking off and think it's "decent, but really confused" with it on. Very smooth shifting.

Edited May 18, 2016 by Dunc

wetcoaster · May 18, 2016

Mine's in the shop since yesterday afternoon for rough shifting and the 'Chevy Shake' at 70mph. Not sure what's happening but I have a loaner 2016 Silverado LT 5.3 with the 6 speed and it seems to shift great!

JacobC1983 · May 18, 2016

Mine's in the shop since yesterday afternoon for rough shifting and the 'Chevy Shake' at 70mph. Not sure what's happening but I have a loaner 2016 Silverado LT 5.3 with the 6 speed and it seems to shift great!

I just drove my loaner 2016 GMC Sierra SLT with the 5.3 and 6 speed for about 1000 miles and I think it shifts very good. With grade braking off it is perfect, but with it on is is substantially better than my 8 speed ever was.