Potential fix for 8-speed and 5.3L

16sierra · March 30, 2017

Guys, just got back from the dealer. I had to get a software update for a recall on the 4wd selector. Something about getting stuck in 4-hi. I mentioned the issues I've been having with the transmission. Mainly harsh downshifts and hesitation taking off from a stop, issues with partial throttle, crawling in traffic, etc. They performed a programming update. Google offered up this when I searched bulletin 4660350: https://www.repairprocedures.com/bulletins/document/16na412/4660350.html

Is this a new TSB? It says Mar 16, 2017. Could somebody with access pull the PDF and post it here? Looks like it says 2016s with the 8-speed and 5.3L.

Anyway, as far as results, it shifted great on my drive home! Knock on wood. Very excited for others to try it out.

AllTerrainX · March 30, 2017

Guys, just got back from the dealer. I had to get a software update for a recall on the 4wd selector. Something about getting stuck in 4-hi. I mentioned the issues I've been having with the transmission. Mainly harsh downshifts and hesitation taking off from a stop, issues with partial throttle, crawling in traffic, etc. They performed a programming update. Google offered up this when I searched bulletin 4660350: https://www.repairprocedures.com/bulletins/document/16na412/4660350.html

Is this a new TSB? It says Mar 16, 2017. Could somebody with access pull the PDF and post it here? Looks like it says 2016s with the 8-speed and 5.3L.

Anyway, as far as results, it shifted great on my drive home! Knock on wood. Very excited for others to try it out.

I would like to see this PDF too!!! Following.

OutBurst · March 31, 2017

I just spoke with my Service Department and this is definitely ONLY for the 5.3L and NOT for the 6.2L. Darn!

mookdoc6 · March 31, 2017

Nice! But.....you will go back into relearn mode and jerk around for another 2-4K and that morning shift out the gate cold 1-2 will still hold onto dear life.......but yeah...I will give it a try.

16sierra · April 1, 2017

Nice! But.....you will go back into relearn mode and jerk around for another 2-4K and that morning shift out the gate cold 1-2 will still hold onto dear life.......but yeah...I will give it a try.

Actually, if I had to guess, I bet they did a service fast learn. It's driving the best it ever has for me (knock on wood). I had all of the problems you mention before.

16sierra · April 1, 2017

I just spoke with my Service Department and this is definitely ONLY for the 5.3L and NOT for the 6.2L. Darn!

If you're having this issue and have a 6.2L, there was a TSB out in December 2016 that people have had mixed success with. Have you tried that update?

Sir Dan · April 1, 2017

I had this update done last week. It drove so well that I thought I was driving a different truck home from the dealer! But alas, it wasn't to last. After about 300 miles I'm back to jerking down into 1st and delayed shift up to 2nd when cold. Why can't they just stop the damn thing from doing the "learn" thing?

16sierra · April 1, 2017

I had this update done last week. It drove so well that I thought I was driving a different truck home from the dealer! But alas, it wasn't to last. After about 300 miles I'm back to jerking down into 1st and delayed shift up to 2nd when cold. Why can't they just stop the damn thing from doing the "learn" thing?

That's a buzz kill.

OutBurst · April 1, 2017

If you're having this issue and have a 6.2L, there was a TSB out in December 2016 that people have had mixed success with. Have you tried that update?

TSB #?

redwngr · April 2, 2017

Mine was done in January. It's been good since the update.

Like others have reported, the prior updates did not solve the problem.

AllTerrainX · April 2, 2017

Guys, just got back from the dealer. I had to get a software update for a recall on the 4wd selector. Something about getting stuck in 4-hi. I mentioned the issues I've been having with the transmission. Mainly harsh downshifts and hesitation taking off from a stop, issues with partial throttle, crawling in traffic, etc. They performed a programming update. Google offered up this when I searched bulletin 4660350: https://www.repairprocedures.com/bulletins/document/16na412/4660350.html

Is this a new TSB? It says Mar 16, 2017. Could somebody with access pull the PDF and post it here? Looks like it says 2016s with the 8-speed and 5.3L.

Anyway, as far as results, it shifted great on my drive home! Knock on wood. Very excited for others to try it out.

So you got an update for the 4WD selector? What is the TSB for that?

Did you get the update for the 4660350 transmission issue yet?

mookdoc6 · April 11, 2017

Going in Today for the annoying couple hard bump shifts every morning when the trans is cold and mysteriously goes away after warm up? We shall see hopefully the programing takes care of it for me which is the only gripe I have with this Transmission.

mruocco · April 12, 2017

Any update? Did you get the TSB installed

f8l vnm · April 12, 2017

Lol. I love these threads. Ain't nothing wrong fellas. It's 100% normal.

mookdoc6 · April 12, 2017

Lol. I love these threads. Ain't nothing wrong fellas. It's 100% normal.

Only with GM does it seem normal? No other automakers Transmission requires "time" or shifting to Remove the bumps/Harsh shifts from an overnight soak? LOL