Torque Converter

[Obxhoops]

I was very close to trading my 2016 GMC Yukon Denali due to the extreme shaking and vibration coming from the tranny/rear area of the truck. As some have described, it was like going over rumble strips. Took it to my dealer and they diagnosed it as a torque converter issue. They drained the trans fluid as per the TSB and it now drives like a new truck. The best part is it was covered under warranty. The GM instructions are to drive it at least 200 miles but the difference was immediate.

 

[Miami-Dade]

Glad it worked out well for you and you are a happy camper again! I would hated to see you have to sell the Denali for a Ford or something else.

 

[FMS1]

I was very close to trading my 2016 GMC Yukon Denali due to the extreme shaking and vibration coming from the tranny/rear area of the truck. As some have described, it was like going over rumble strips. Took it to my dealer and they diagnosed it as a torque converter issue. They drained the trans fluid as per the TSB and it now drives like a new truck. The best part is it was covered under warranty. The GM instructions are to drive it at least 200 miles but the difference was immediate.

I have a 2016 Denali 4-WD with 61,000 miles and having exactly the same problem. I notice it more when switches to 4-cylinder under slight load. Does anyone have the TSB number for this fix? I appreciate the help.

 

[MechEng813]

Mine is in right now for exactly this @54k.
Been a week so far, because a trans temp sensor was on backorder.
Hope it resolves it, been considering a Model S 90d.

 

[G00se]

I have a 2016 Denali 4-WD with 61,000 miles and having exactly the same problem. I notice it more when switches to 4-cylinder under slight load. Does anyone have the TSB number for this fix? I appreciate the help.

I’d like to know as well. Same truck, year, miles, drive, and issue as mine.

 

[dbbd1]

I’d like to know as well. Same truck, year, miles, drive, and issue as mine.

I have a 2016 Denali 4-WD with 61,000 miles and having exactly the same problem. I notice it more when switches to 4-cylinder under slight load. Does anyone have the TSB number for this fix? I appreciate the help.

Have either of you tried the bolt mod? If it seems to happen going into or in V4 mode, you may just be feeling/hearing the flapper.

 

[G00se]

Have either of you tried the bolt mod? If it seems to happen going into or in V4 mode, you may just be feeling/hearing the flapper.

I plan to do the bolt mod anyway so I'll report back. Fingers crossed.

 

[G00se]

Found this as it seems related, going to give it a try.

 

[dbbd1]

Do you have the 8-speed trans?
That's what the TSB is for.

 

[coacht]

I had this service, flush and software reprogram done last week on our '16 8 speed. And haven't had an issue since.

Cost me $635 out of pocket. But the way it was driving I was afraid it was going to be something worse than this. So I was glad to only pay the $635.

 

[justinb181]

I had this service, flush and software reprogram done last week on our '16 8 speed. And haven't had an issue since.

Cost me $635 out of pocket. But the way it was driving I was afraid it was going to be something worse than this. So I was glad to only pay the $635.

With this being a TSB shouldn't it have been covered by the dealer even if you are out of warranty?

 

[dbbd1]

Not necessarily, unless it's a safety thing.

 

[dapapa]

I have a 2015 YD with 75k. It developed the vibration. Dealer finally agreed it was the torque converter and did the replacement under warranty. Just drove to Canada and back and it ran great. It also decreased the transmission clunk in low speed downshifting by 75%

 

[wu6fiend]

I'm taking my 2016 Yukon Denali to the dealership, first chance I get. It feels like you are driving with the emergency brake on (it isn't), and is occasionally shifting hard. But at low speed, under light throttle, it shudders and shakes (just as described in the service bulletin). Compared to my previous Denali (2009), which was smooth as glass in all conditions, powertrain wise. I haven't really liked this 8 speed from day #1, and now have the documentation (the service bulletin) to show to the service advisor.

 

[Tee202]

I have a 2016 Denali brought brand new. took it out for a drive Friday and Serious vibrations throughout the truck even when switching gears. Called the dealership and they mentioned torque converter....will be going in tomorrow with 44k miles. Plus sometimes at low rpm it also snatches really hard into second gear. Hopefully they can fix this issue or so long GMC I miss my Honda anyways.

 

[Tahoe14]

They may do a fluid change and re-program first and then the TC replacement which is protocol for GM. The fluid change and re-program has fixed several trucks and SUVs.

 

[wu6fiend]

Mine has been kept overnight at the dealership. They say they want to reflash the transmission's programming or some such thing. When I dropped it off this morning, I took it for a road test with the service manager, and complained of the things I have noted about this transmission (of it selecting a higher than optimal gear under light throttle while the vehicle is on an upgrade, of the occasional hard upshifts, and hard downshifts, and the transmission's seeming confusion at times as to what gear it should be in); he said he has heard these comments from other 2016-2017 owners with the 8 speed transmission before. At the end of the day, I may have to just live with this transmission. Apparently my symptoms are not those of a defective torque converter, which feels like the vehicle is being driven over continuous rumble strips. I wish this 2016 had the powertrain of the 2009 (its predecessor), I liked it better, driving experience wise.

 

[Tahoe14]

What did he say about the fluid change. He needs to look at what GM recommends for the issues you have described not what he thinks, I would push him for the re-program and fluid change as recommended by GM.

 

[wu6fiend]

Ok, so picked up the Denali this afternoon, and went for a drive. I took the exact route that used to highlight the transmission issues, and prompted my trip to the dealership.

The service invoice says the following, "Roadtest to verify concern, check ECM/TCM with latest software, warranty claim code #---------, roadtest vehicle to specified temperature, perform fastlearn, roadtest vehicle and set transmission clutch volumes for individual clutches, learn clutch return spring values, verify repair."

There is a noticeable improvement in drivability. The shifts are much smoother, the rattle from the AFM (during the V8 to V4 switch) is now absent, and the overall vehicle, believe it or not, is much quieter. There isn't that "bogging" feeling that I got (no other way to describe it, it felt like the transmission was in too high a gear at low throttle on an uphill grade).

I'm quite surprised that a software refresh could make such a change.

It feels overall much better. Pretty happy right now!

 

[swathdiver]

That's good news Patrick. Seems that the adaptive functions, the transmission adjusting itself for best performance, as it aged were not working so well.

 

[wu6fiend]

The shop foreman, during our road test, said my observations of the 8 speed (the occasional hard up or downshift, the bogging feeling) were shared by other 2016-2017 owners. He also said that they had received complaints from owners of the 2018-newer 10 speed, too. Apparently some owners are irritated by that transmission's constant hunting for the right gear, shifting up and down constantly, never happy with its choice. Having never driven a 2018-newer model, I cannot comment.