Torque converter shudder continues

Willborio · September 8, 2018

I have an 18 denali. I have 3600 miles on it and about 1000 miles ago I notice a vibration in the steering wheel. At times it will get the column shifter bouncing around. It's only under light load on the engine. If i let my foot of the gas or hammer down its smooth. Could this be the same issue as the torque converter?

Doublebase · September 9, 2018

After reading this thread I think what I'll do is change my Fluid and filter at 20,000 miles - I'm at 12,000 miles now - 5.3 six speed, but I do get some harsh shifts, etc. Never considered that the initial break in period and material from the clutch packs could be putting some gunk in the converter. But I guess it could.

Pearl2017 · September 10, 2018

On 9/7/2018 at 7:33 PM, Willborio said:

I have an 18 denali. I have 3600 miles on it and about 1000 miles ago I notice a vibration in the steering wheel. At times it will get the column shifter bouncing around. It's only under light load on the engine. If i let my foot of the gas or hammer down its smooth. Could this be the same issue as the torque converter?

It could be TCC related Chuggle. On mine it felt like i was hitting small potholes the steering wheel would buzz for a secont at a time ...even on a brand new smooth asphalt street.

Pearl2017 · September 10, 2018

Part of the FLUSH and filter change process involves getting the trans up to temp and running a CLEANING routine that is built into the trans controller. The procedure involves a tech with his foot on the brake moving the gear selector at specific times. What happens inside the trans is the valves are cycled repeatedly as fluid is pumping through to clear any debris or varnish buildup. At the same time a re-calibration of the actuating pressures is done based on variables like wear/thickness of the clutch pack/s material. It is quite complex.

If the tech is not running the CLEANING routine and only changing fluid then the problem may not go away.

samckitt · September 19, 2018

Has anyone tried this stuff to resolve the shudder issue? Members on the Colorado/Canyon forum have stated they have good luck with it.

Dearmosd · January 13, 2019

Well after continuing my search for the small vibrations i feel in the steering wheel and everyone looking at the tires//suspension I put my 2018 Suburban into tow mode and felt a quick difference in the vibration issue.

In Tow mode I felt a decrease in vibrations in the steering wheel and column and quickly went home to do my research until I found the TCC shutter also linked to the 6L80 transmissions. I saw this issue more linked to to the 8 speed trans but didnt find any bulletins linked to the 6 speeds. I guess I will be scheduling a service appointment to look into this along with my first oil change.

426power · January 17, 2019

Well took my 2018 GMC Sierra Elevation addition 5.3 6 speed in yesterday for the dreaded shutter. Their "transmission specialist" has ordered ma torque converter to be installed next week. I just don't understand why GM did not correct this on the line when these trucks were being built after all the trouble they have had.

SS502 · January 17, 2019

9 minutes ago, 426power said:

Well took my 2018 GMC Sierra Elevation addition 5.3 6 speed in yesterday for the dreaded shutter. Their "transmission specialist" has ordered ma torque converter to be installed next week. I just don't understand why GM did not correct this on the line when these trucks were being built after all the trouble they have had.

Sorry to hear that...I thought that GM stopped changing the TC and now just flush and fill? I hope I never have to go through what you are and wish you the best of luck getting that problem fixed.

Dearmosd · January 17, 2019

How did you diagnose the issue or explain it to the service tech. I think I might be in the same boat. I can just feel a lack of smoothness when it shifts and goes to V4 mode. It seems to shift a lot when traveling in the 0-45mph range. I feel tow made makes it smoother in between shifts.

426power · January 17, 2019

51 minutes ago, Dearmosd said:

How did you diagnose the issue or explain it to the service tech. I think I might be in the same boat. I can just feel a lack of smoothness when it shifts and goes to V4 mode. It seems to shift a lot when traveling in the 0-45mph range. I feel tow made makes it smoother in between shifts.

When i'm driving between 30 to 35 mph at a steady pace then accelerate very slightly I get a shutter vibration and it sounds like the exhaust rattles. The tech was able to reproduce it from what I told him. He has done the fluid change and replaced several torque converters in the past. He said my truck had the updated fluid and from the what the truck is doing its definitely the torque converter.

Dearmosd · January 18, 2019

On 1/17/2019 at 11:35 AM, 426power said:

When i'm driving between 30 to 35 mph at a steady pace then accelerate very slightly I get a shutter vibration and it sounds like the exhaust rattles. The tech was able to reproduce it from what I told him. He has done the fluid change and replaced several torque converters in the past. He said my truck had the updated fluid and from the what the truck is doing its definitely the torque converter.

please report your feedback after the tC swap please

2017Darkness · January 21, 2019

On 7/4/2017 at 9:58 AM, Bigmac said:

2017 Sierra 6.2 8 speed max tow. 3500 miles. Still has shudder even though converter replaced and new type fluid installed. Has anyone else have the continuing problem or has it been corrected? Shifting on mine is good but the shutter is bad especially when towing.

They did the procedure wrong...should not have replaced the converter. 98% of the time it's one and done...

HondaHawkGT · January 24, 2019

Just thought I'd pass this on. This info was just posted last week on the Corvette Forums. I turns out the ATF fluid they've been using is hygroscopic, which is why the transmission shudder usually goes away after a flush but eventually starts to come back.

https://www.corvetteforum.com/forums/c7-general-discussion/3999067-a8-transmission-failure-tracking-46.html#post1598716902

Quote

Due to the availability of the new Mobil 1 HP fluid and required tool kit, the procedure will be rolled out regionally starting in the Southeast and South-Central regions due to the frequency of TCC shudder. This concern is related to moisture. The current HP fluid has a greater tendency to be hygroscopic – or water absorbing. It also tends to hold that moisture even when the fluid heats up. As the moisture content in the fluid increases, the tendency to have TCC shudder increases. Selected dealers received a Global Connect Message sent to the attention of the Service Manager the week of December 3 advising them of the new service procedure, tool shipment and fluid availability. The Global Connect message includes a PDF copy of the service procedure. It is anticipated that the Mobil 1 Synthetic LV ATF HP and required tool kit will be available to all dealers by March 2019.

Mobil 1 Synthetic LV ATF HP will only be available through your local GM Oil Distributor. The new oil formulation will initially be available in 55-gallon drums. Drums will cease production in January 2019 and will change to quart bottles.The quart bottle will not have a GM part number on the bottle. The bottle however has been updated. The back ground of the bottle where it states “Synthetic LV ATF HP” has changed from black to blue. (show bottles) The license number on the back of the bottle has changed to J-62120. The six pack packaging has been changed from black script on the white box to blue script on the white box.Dexron HP Fluid, part number 19417904 for a 55 gallon drum or 19417577 for quart bottles.

Edited January 24, 2019 by HondaHawkGT

DeePa · January 25, 2019

I had the first 2017 6 speed chuggle TSB don't on my 5.3 back in match 2017. Truck now has 49000 and its back again. Asked the dealer about it, and they stated that there will be a new TSB in Feb and he will take my truck in then to repair the issue. Just a FYI for all. What he was talking about sounds very similar to the stuff on Corvette Forum. ATF absorbing water and causing a bunch of havoc. I'll post up when the TSB has been done.

Mike

NomadicCPO · January 27, 2019

On 1/25/2019 at 1:37 PM, DeePa said:

I had the first 2017 6 speed chuggle TSB don't on my 5.3 back in match 2017. Truck now has 49000 and its back again. Asked the dealer about it, and they stated that there will be a new TSB in Feb and he will take my truck in then to repair the issue. Just a FYI for all. What he was talking about sounds very similar to the stuff on Corvette Forum. ATF absorbing water and causing a bunch of havoc. I'll post up when the TSB has been done.

Mike

My local dealer telling me same thing. While I’m happy that they may finally have a permanent solution, I can’t help but wonder if it is indeed water-absorbing ATF what kind of damage has been done to the clutch packs. I’m not a transmission guru but I do know water doesn’t play nice with the internals.