2015 driveline vibration

177mph · July 10, 2017

2015 GMC Sierra Denali 6.2 long bed. Factory 22's. No modifications. 39k miles. I have been experiencing a vibration in the steering column and seat at low rpm from 20-60 mph. Usually below 2k rpm when at low throttle application. Vibration comes every few seconds and lasts 2 seconds. Not from the v8-v4 switch. Only thing that helps is running in tow/haul mode or manually shifting. Truck has also been in for service a few times with loud metallic bangs for upshifts and downshifts. Dealer found nothing. No codes.

Is anyone else experiencing similar issues?

Thanks.

mookdoc6 · July 10, 2017

2015 GMC Sierra Denali 6.2 long bed. Factory 22's. No modifications. 39k miles. I have been experiencing a vibration in the steering column and seat at low rpm from 20-60 mph. Usually below 2k rpm when at low throttle application. Vibration comes every few seconds and lasts 2 seconds. Not from the v8-v4 switch. Only thing that helps is running in tow/haul mode or manually shifting. Truck has also been in for service a few times with loud metallic bangs for upshifts and downshifts. Dealer found nothing. No codes.

Is anyone else experiencing similar issues?

Thanks.

Foaming of the Transmission fluid? Do you have the 8L90 mated to it mate? Than you need to flush/fill that pooch!

177mph · July 10, 2017

I have the 8 speed. Is that the same?

177mph · July 17, 2017

It would seem from my research on the boards that it could be the converter in the 8 speed transmission. Truck vibrates badly at times below 2k rpm at light throttle.

dgirouard39 · July 18, 2017

staying on this thread... curious to see what people say

177mph · August 3, 2017

here's the update. Truck is at stealer. I gave them all the information on the trucks condition and the GM documented fixes (They seem to hate being told how to fix). The vibration is consistent with other trucks and is related to the transmission. The fix listed on GM's diagnostics site is converter replacement and a fluid flush. They are refusing to do the converter replacement and only doing the fluid flush. I cannot get them to change their repair no matter what I do. I will hopefully get the truck back tomorrow and see how it goes. I am expecting the same issue to come back in 3 months. Time for another brand.

L86 All Terrain · August 3, 2017

Have another dealer look at it. Many will if they can pursuade you into favouring their dealership. They swapped my TC out on my 2015 6.2 8spd before i even got to drive it, awesome truck no issues, no vibration or weird clunky shifts. My 2014 5.3 w/ 6spd is another story, embarrassing to drive really due to Chevy shake.

Blue17 · August 4, 2017

I took mine to the dealer with the same issues, we got tires all set after 3 new ones and multiple road force balance attempts , they showed me where GM will not allow dealers to change the converter anymore as the original version of that TSB stated. they did do the triple flush with the Gucci fluid. it was better but not completely gone. its vibrates at 65-75 I brought it back and they checked some more things and contacted GM, they explained to me that GM wanted them to check TCC slip speed at 60mph and if it were more than 10 RPM's to change the converter, they checked it, it was 26 RPM's and they put a new converter in it. so far (knock wood) it seems to be corrected. they also let me know that the TC part number has been changed 4 times since they did one other swap in April of 2017. they said that sometimes means there was changes made to correct issues.

I think the dealers are behind the 8 ball on this issue, GM doesn't always tell them the whole story either, so they can only do what they are allowed to. So far my dealer has been very good to me on this issue they have not stopped trying. I am very happy with their service. I just hope I wont need to see them anymore for a while.

hotrdlx · August 4, 2017

I am having the same issue with my 2015. The torque converter has already been replaced once for this exact same issue. The transmission tech at the dealer told me that it the shuttering was not bad enough yet and to keep driving it until the vibration and shuttering gets worse. No diagnostic tools were connected to find out the amount of slip. They were also hesitant to work on it as it had been less than a year since the first replacement.

Does gm give dealers a hard time about warranty repairs if they have a reoccurrence within a year? Obviously this would not be due to anything the dealer did or did not do but just poor parts quality or design issues.

I know the gm customer service people lurk on the board how about providing contact information to someone that can give us a straight answer to the ongoing issues with these 8 speeds.

TX15Z71 · December 1, 2017

Hey 177. Any update? Did the fluid flush help at all? My 2015 is starting to do the exact same thing. About 35k on the odometer.

TX15Z71 · December 29, 2017

I took mine in to the dealer for the shuddering between 20 and 50 mph. They did a transmission fluid flush 8 times. Yes 8 times. That's what the manufacturer is calling for. My vibrations are gone for now. Hopefully this was a permanent solution.

orangedeluxe · October 12, 2021

Did the fluid flush fix it long term? I’m having a similar issue on my 2015 Sierra Denali I just purchased.

lucas287 · October 13, 2021

14 hours ago, orangedeluxe said:

Did the fluid flush fix it long term? I’m having a similar issue on my 2015 Sierra Denali I just purchased.

You very well might need the new updated "blue bottle" ATF. However, I think a lot of folks are experiencing axle wrap and general vibrations from unequal operating angles. Just my two cents.

I've been down this road myself and blamed it on the 8 speed or the TC. After the dealer flushed with new fluid I thought it was all better but it was just placebo. That's when I started going down the path of operating angles. With a one-piece driveshaft the angle of the t-case/transmission output shaft needs to be equal (and opposite) to the pinon angle. Once I got that nailed (with shims) I installed some traction bars and voila - no vibes. These direct-injection engines punch above their weight class down low in the torque department. The L83 is more akin to the coveted LQ4 and the L86 makes big-block torque. You can't control that torque with the crappy leaf design GM uses.

Pam McC · November 2, 2021

Hi, I was told by the service manger at my dealer that the torque converter needs flushed and driven 3 times and there’s a COMPUTER UPDATE that needs to be done to rectify the problem! If that doesn’t solve the problem then replace the torque converter.