Who likes their 8 Speed?

[CRApex]

I didn't like mine at first...It has 3000 miles on it now (6.2 8spd) and now that it seems to have "learned" I'm actually really liking it.

[JacobC1983]

Jacob, Just got done driving about 20 miles in various conditions. No change from driving in M7 except worse MPG from the higher RPM's on the highway.

Thanks for the update. I figured as much.

[JacobC1983]

The field service engineer was completely wrong... I disabled grade braking and drove around in manual 7 and the truck still has clunking shifts.

 

My service advisor is letting me know next week about the trade assistance and buyback options.

[wetcoast]

 

 

Hi Chris,

I am always happy to help. Thanks for reaching back out. I look forward to receiving your PM. In the meantime, if you have an additional questions please feel free to ask.

Have a great day.

Julianne M.

GM Customer Care

I have the truck back. Still clunky shifts as expected. The dealer put 3 new tires on the truck because 3 out of 4 tires were so out that they wouldn't balance. All of this with 5600km on the odometer. These factory tires are now proven to be very inconsistent.

[mookdoc6]

the rims are probably pretty inconsistent too. goodyear tires are only good for going 90mph around a corner and wearing out in 35,000 if your lucky..........IMO been the biggest joke in tire industry for years! Get em wet and they are straight dangerous!

[5829BMG]

Anyone have P to D and/or P to R cold harsh/delay engagement??

[thetruck454]

I do on occasion

[seamus2154]

Anyone have P to D and/or P to R cold harsh/delay engagement??

 

This is a known issue for many guys mainly 2016 models. There is a TSB out on it in one of these transmission threads. Dealer should know about it. It involves changing some plate that now has a check ball so it doesn't leak down when left for long periods. Oh here it is I found it:

 

http://www.gm-trucks.com/forums/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=61340

[wetcoast]

Anyone have P to D and/or P to R cold harsh/delay engagement??

Yep. More prominent when shifting on hills

[bosro]

Jekyll and Hyde....

That's how I see my 8 speed.

Clunky....weird shifts some days.

Smooth and predictable others.

Sadly the Clunky weirdness is the majority of time.

Any hard acceleration seems OK but idling around town and coasting to stops usually gives a good clunk of some type.

V4 mode may have something to do with so I went and ordered the Range device to disable it.

No I did not want to tune it....I believe something will break eventually so I'm taking no chances with warranty.

Some of clunking sounds like coming from rear end.

I've resigned myself to driving it till it breaks....and I refuse to sit truck at dealership for days or weeks.

Either it breaks or I do....

[bosro]

Guess I'll just drive the shit out of it and see what happens

Edited May 23, 2016 by bosro

[5829BMG]

 

This is a known issue for many guys mainly 2016 models. There is a TSB out on it in one of these transmission threads. Dealer should know about it. It involves changing some plate that now has a check ball so it doesn't leak down when left for long periods. Oh here it is I found it:

 

http://www.gm-trucks.com/forums/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=61340

 

Can some one post this TSB in its entirety

[zert100]

That doesn't work for the 8 speed trucks, thanks though. I have tried it, and many others in the thread with 8 speeds haven't had luck with it.

 

doesn't work with the 6 speeds either...

[tmw22]

I've had my 2016 with 5.3 and 8 speed for about 3 wks now and almost 1000 miles, it has never acted funny at all. It always goes into gear immediately and haven't heard or felt the first clunk yet. So far I am loving this tranny and this truck, hope I didn't jinx with this post ?

[scottp1108]

One week in, about 600 miles, all seems to be well with it. Had a couple times where I felt a little something while slowing then accelerating, but nothing to write home about. Hope it keeps up.