Who likes their 8 Speed?

Snoringbear · November 10, 2016

Wow snoringbear. Thank you. I will be forwarding this article to gm and bbb. They keep telling me there's nothing wrong. As designed. Well if that's the case I can't understand why they would design it to clunk and bang. Seams like it wouldn't last very long or the u joints or rear axle for that matter.

Yeah, agree. I had something similar going on with mine. So, at the last oil change, brought it up. Tech reset the tranny back to factory spec's so it would relearn my driving style. Seemed to help. Btw, I will try to remember to post the next TT update on their Long Term Denali Evaluation.

Srode1 · November 11, 2016

Yeah, agree. I had something similar going on with mine. So, at the last oil change, brought it up. Tech reset the tranny back to factory spec's so it would relearn my driving style. Seemed to help. Btw, I will try to remember to post the next TT update on their Long Term Denali Evaluation.

I had mine in for the seat belt tensioner recall / reflash and they updated the TCM with the latest calibration and set it to rapid relearn when I mentioned the shifting problem (very helpful and I didn't buy the truck from them either). The harsh shift I was getting mostly cold was the 4 to 5 shift up and occasional down shift when slowing. The downshift slowing problem is gone completely, and the 4 to 5 upshift when cold harshness is much less frequent and less severe when it happens. It will probably take a few thousand miles for the relearn to work it's way through the process, but I'm cautiously optimistic for now.

Snoringbear · November 11, 2016

I had mine in for the seat belt tensioner recall / reflash and they updated the TCM with the latest calibration and set it to rapid relearn when I mentioned the shifting problem (very helpful and I didn't buy the truck from them either). The harsh shift I was getting mostly cold was the 4 to 5 shift up and occasional down shift when slowing. The downshift slowing problem is gone completely, and the 4 to 5 upshift when cold harshness is much less frequent and less severe when it happens. It will probably take a few thousand miles for the relearn to work it's way through the process, but I'm cautiously optimistic for now.

Wish I knew more about the tranny learn/relearn feature. Anybody out there who can shed a little light on this? Would be most appreciative

silver sled 16 · November 11, 2016

Ok update. Today in the way home from work stop and go traffic my trans in second gear suddenly slipped into neutral when I went to accelerate. It then slammed back into gear incredibly hard. I now have consistent vibration that increases with speed. I'm guessing drive shaft is bent or maybe something worse. I have appointment on 22nd at different dealer as per gm. Can't wait to see how they explain how this is operating as designed now. So sad . This is one he'll of a beautiful truck and I love it but this is getting nuts now. I post results of dealer visit for those that are interested in out come. P.s. I average 18 mpg with truck and baby it better than an old man. At 56 thousand dollars it needs to last and retain value.

Edited November 11, 2016 by silver sled 16

Srode1 · November 11, 2016

Wish I knew more about the tranny learn/relearn feature. Anybody out there who can shed a little light on this? Would be most appreciative

This is a good description of how it works and what can be done to correct specific shift problems.

http://gm.oemdtc.com/492/transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-2015-cadillac-chevrolet-gmc

Snoringbear · November 12, 2016

This is a good description of how it works and what can be done to correct specific shift problems.

http://gm.oemdtc.com/492/transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-2015-cadillac-chevrolet-gmc

Thanks. A good read. I wonder though, after having reset the quick learn feature, how many techs do a test drive with tranny temp warmed to spec and individually reprogram each clutch as needed. Not many I'm guessing.

Srode1 · November 12, 2016

Thanks. A good read. I wonder though, after having reset the quick learn feature, how many techs do a test drive with tranny temp warmed to spec and individually reprogram each clutch as needed. Not many I'm guessing.

If you go to the end of the second page you can see the warranty labor time paid is actual time not book time so they get paid pretty well to do the work as including the test drive to make sure the rapid learn feature does what it is supposed to vs just relearning the old shifting that caused the problem to start with. Most dealer techs are on flat rate I would guess.

Edited November 12, 2016 by Srode1

Snoringbear · November 12, 2016

If you go to the end of the second page you can see the warranty labor time paid is actual time not book time so they get paid pretty well to do the work as including the test drive to make sure the rapid learn feature does what it is supposed to vs just relearning the old shifting that caused the problem to start with. Most dealer techs are on flat rate I would guess.

Good to know. Thanks for pointing that out.

mookdoc6 · November 14, 2016

Yup, they just plug it in and fast relearn it......Never take the time to drive it around and dial in the clutch packs?

silver sled 16 · November 15, 2016

Sounds like what keeps happening to me every time I bring it in.

cbr9rider · November 15, 2016

Does anyone's truck sometimes feel like you are running over rumble strips? Mine has done it in the past but dealer changed something in the trans, fixed it right up until this past week it started doing it again around 50-60 MPH at low throttle.

silver sled 16 · November 16, 2016

My truck did that on the way home from purchase and continue to do it until my torque converter was replaced. There is a bulletin to replace converter and flush trans. My clunking began soon after. I'm thinking they did a fast relean and cleared all factory loaded data thus creating shifting issue.

Dans Denali · November 16, 2016

2016 Denali 5.3 8 speed with 6000 miles and no complaints. Are the 6.2 people having more issues than the 5.3?

Dan

TXAG90 · November 16, 2016

I have a 2017 silverado with the 6.2. I have 4k miles on it.

The tranny can be a little clunky on the downshift, and upshift with light acceleration, in the first couple of gears. The 8 speed with the 6.2 on the highway is absolutely fantastic. An incredible improvement over my 2011, on the highway. I get 22-23 mpgs on the highway running premium shell gas. the lifetime gas mileage is 20 mpg. Not bad for a 4x4 crew cab.

I have the range afm disabler on my '17 and it does improve the driving experience. No drone, better throttle response and no v4 lag. Haven't sacrificed and fuel economy, as far as I can tell. Best mod you can do, IMO.

My last truck was a 2011 silverado with the 5.3 and 6 speed. I experienced the same kind of "clunky" shifts on it as well. I'll also note I traded that one in with about 100k miles on it with no issues. I got 15 mpg in city and on the highway.

Dmf10e · November 16, 2016

I have a 2017 silverado with the 6.2. I have 4k miles on it.

The tranny can be a little clunky on the downshift, and upshift with light acceleration, in the first couple of gears. The 8 speed with the 6.2 on the highway is absolutely fantastic. An incredible improvement over my 2011, on the highway. I get 22-23 mpgs on the highway running premium shell gas. the lifetime gas mileage is 20 mpg. Not bad for a 4x4 crew cab.

I have the range afm disabler on my '17 and it does improve the driving experience. No drone, better throttle response and no v4 lag. Haven't sacrificed and fuel economy, as far as I can tell. Best mod you can do, IMO.

My last truck was a 2011 silverado with the 5.3 and 6 speed. I experienced the same kind of "clunky" shifts on it as well. I'll also note I traded that one in with about 100k miles on it with no issues. I got 15 mpg in city and on the highway.

Can you use it in a V6? And will it void the warranty?