My own 8 speed problems & resolution

Dcollins25 · November 20, 2016

Wow that is some great info, I wonder if that's the end all be all of fixes for all of this? That would explain why multiple people including myself had replacement transmissions that just never seemed to make much difference. Is that what they fixed for the 2017's? Again, look at my latest post if you have the time. Why would GM lemon law their own truck, and crush a truck if that was the fix for it?

4emeryj44 · November 20, 2016

I am back in on monday for the valve body.hope it cleans up the last 5% of the problem. I will get the update number for you.

Okay that would be great. Monday is my make or break whether I take the truck back or go with the trade in. Again I appreciate that info. If that would guarantee fix my truck I'd like to look into that.

DCollins - you quoted me but with no response???

Dcollins25 · November 21, 2016

The stator support shaft update number is 16-na-014 it's not a normal one number and it was applied to my 2015 Sept build 6.2l . That said if you have the same symptoms in your 5.3l I would insist on having it changed.

GullLakeMi · November 22, 2016

I have '16 Denali 6.2 w/8 speed. Same issues at start-up, idle in gear jerkiness. Also, lower speed (40-45) with cruise clunky shifts for no reason. Downshift, upshift clunks. Be great to hear of any success stories.

shadowmn · November 22, 2016

I am back in on monday for the valve body.hope it cleans up the last 5% of the problem. I will get the update number for you.

Yes, please get that number!! Thanks for the info!

Dndodd · November 22, 2016

The stator support shaft update number is 16-na-014 it's not a normal one number and it was applied to my 2015 Sept build 6.2l . That said if you have the same symptoms in your 5.3l I would insist on having it changed.

Here is a whole thread on this issue;

http://www.gm-trucks.com/forums/topic/187484-delayed-engagement-on-the-8l90e/

Dcollins25 · November 22, 2016

The stator support shaft update number is 16-na-014 it's not a normal number and it was applied to my 2015 aug build 6.2l . That said if you have the same symptoms in your 5.3l I would insist on having it changed. My truck now has 14000 miles and ito shifting is almost perfect.

Eric Ward · July 19, 2017

OK truck has been at dealership (not from where truck was purchased) for about a week now because of steering wheel vibration and clunky transmission and also when left over night you start up in the morning it takes a few seconds for the reverse to grab. The dealership allowed me to drive a brand spanking new Tahoe Platinum so guess I cant complain. So the first time me and service personal talked he said the Torque Converter would be replaced and that GM wanted them to empty out the transmission fluid and refill with different type. I will let him know about the 16-NA-014 Bulletin. I am sure he knows about it. Since I'm not going to mention the dealership at this point the technician told me they were have alot of issues with the 8 speeds. I love my truck and the power of the 6.2.

Eric Ward · July 25, 2017

Update: Getting new torque converter and new fluids. Will let ya know how that does. I do know the Tahoe they've been letting me drive shifts butter smooth.

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Rme2513 · July 27, 2017

Update: Getting new torque converter and new fluids. Will let ya know how that does. I do know the Tahoe they've been letting me drive shifts butter smooth.

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The new torque converter fixed my vibrations but not the slow engagement in reverse

Eric Ward · July 27, 2017

Rme2513 did you have the Stater Support Shaft Update 16-NA-014 done on your truck?

MrNasty · July 27, 2017

Also check if they did TSB 16-NA-411. Its TCM update. They did my torque converter not for vibration but RPM fluctuation and my stator assembly for delayed engagement. Was better for short time then delayed engagement was worse than before. I had the TCM update almost 2 months ago and truck shifts better and no more delayed engagement.

MOhunter92 · August 1, 2017

Had a tcm update done to my transmission 2016 sierra all terrain slt, 5.3 8 speed (it was absolutely horrible and I dreaded driving it, terrible 3-1 down shift and sloppy shifting overall, very severe clunks and shudders) and literally feels like a different truck. It is smooth as silk, I am absolutely thrilled. It was a one year battle for me to try and get this truck to shift right. I'm so excited, still in shock! I will be sure to post the service receipt once I get it.

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Rme2513 · August 14, 2017

Rme2513 did you have the Stater Support Shaft Update 16-NA-014 done on your truck?

Yes it was done before the torque converter went bad

JUS1MO · August 30, 2017

I have all the same problems as most here with my 2017 GMC Sierra 1500 Z71. I have the 5.3/8 Speed. Very interested if a fix as the Dealer did the fast learn at 500 miles with no correction. Was told to just drive it until the first oil change at 5000 miles to see if things improve. At 3400 miles now, no improvement yet..