2019 Silverado RST 8 speed automatic transmission

econometrics · September 5, 2019

11 minutes ago, Jethroy Potter said:

Talked to my dealer and showed them a copy of TSB 19-NA-121 and they say it doesn’t apply to the problem with my truck. I’m getting an extremely hard shift between first and second as well as second to first. The problem is intermittent but the last time was the worst. Gradually accelerated and there was a loud bang when it went from first to second. The truck almost stopped then lunges forward. Luckily nobody was in front or behind me. I thought for sure something broke.

Sorry you're having to mess with a stubborn dealer.

The bottom line is that the TSB is out, and they should change the fluid. Sure, maybe it won't help your harsh shifts, but it also doesn't hurt. Tell them you want it done, as GM says it needs to be swapped.

Jay P · September 5, 2019

There are owners of the Colorado/Canyon with the 8 speed that have reported the harsh 1 to 2 shift was fixed with the Blue label MobilOne trans fluid specified in the two TSBs (one TSB for the T1s and one for everything else).

Jay

KCunn21 · September 5, 2019

Sorry to be a pain in the ass but I can’t get a link for the TSB that affects the Silverado.. the link that you posted is for Colorado..

Jay P · September 5, 2019

1 hour ago, KCunn21 said:

Sorry to be a pain in the ass but I can’t get a link for the TSB that affects the Silverado.. the link that you posted is for Colorado..

It's on the 1st page of this thread.

Jh8473 · September 6, 2019

I will do it myself when i get board.

HondaHawkGT · September 10, 2019

On 9/5/2019 at 7:37 PM, Jh8473 said:

I will do it myself when i get board.

Changing trans fluid on the 8-speeds isn't as easy and straightforward as it was on older transmissions. Like totally different and requires a computer to finish the procedure correctly or it might shift like shit.

KCunn21 · September 11, 2019

Does anyone have the updated TSB that shows that testing does NOT need to be done? There is only one posted dated June.. I believe there is one dated July 2019 staying testing does not need to be done..

Gsmith308 · September 16, 2019

On 9/11/2019 at 5:20 PM, KCunn21 said:

Does anyone have the updated TSB that shows that testing does NOT need to be done? There is only one posted dated June.. I believe there is one dated July 2019 staying testing does not need to be done..

I’d like to have that one as well.

Trail Jefe · September 18, 2019

I was also told that this doesn't apply to mine! He said I have a different transmission.... are there 2 different 8 speed?

Jay P · September 18, 2019

2 hours ago, Trail Jefe said:

I was also told that this doesn't apply to mine! He said I have a different transmission.... are there 2 different 8 speed?

Sort of there is an 8L45 and an 8L90 but the Silverado as only had the 8L90. When was your truck built? Starting in March they had the new fluid from the factory and that may be why it doesn't apply.

Jay

Edited September 18, 2019 by Jay P

KCunn21 · September 18, 2019

Ok.. so I just picked up my truck from dealership.. I am told that the valve body needs to be replaced and while that is being done the transmission fluid will be flushed to the Mobile 1 which was talked about in the TSB.. The transmission specialist tells me that the jerking is not due to the truck not having the Mobile 1 but it is directly related to the valve body but the transmission fluid will be flushed as well.. anyway.. we will find out when the get the part in and the work is finished.. I will keep you posted..

Jethroy Potter · September 18, 2019

Got my truck back last week from the dealer. They say it’s not the fluid it’s a solenoid valve that’s sticking and needs to be replaced. Of course the part is on back order and they have no idea when they’ll get the part.....