How are the current 8spds on 2021 trucks?

Jim165 · March 8, 2021

In looking around at 2021 Sierra SLT 5.3s with X31, there are a lot that have the 8spd tranny installed instead of the 10spd. I’d prefer the 10 spd by far but it gets difficult to see online which trans it has due to GM’s piss-poor VIN build lookup. How are the 8spds now that the fluid was changed? Any anecdotals from current owners? Thanks

SummitWhiteT1 · March 8, 2021

I have a 2021 with an 8spd. I traded in a 2019 that also had the 8spd and it was a night and day difference. I would get all the usual 8spd complaints in the 19 but none of them in the 21. The only thing I can't comment on is if the 10spd shifts faster than the 8spd. I never drove a 10spd to compare it to

patrickjlindsay · March 8, 2021

In looking around at 2021 Sierra SLT 5.3s with X31, there are a lot that have the 8spd tranny installed instead of the 10spd. I’d prefer the 10 spd by far but it gets difficult to see online which trans it has due to GM’s piss-poor VIN build lookup. How are the 8spds now that the fluid was changed? Any anecdotals from current owners? Thanks

Didn't GMC downgrade all of 5.3 SLT's to the 8 speed late last year? According to the Build and Price site right now, 5.3 SLTs get the 8 speed but 6.2 and 3.0 diesels get the 10 speeds.

I would get the 6.2 or the 3.0 just to avoid the 8 speed.

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lebag335 · March 8, 2021

I have a 9/11/20 built '20 AT4 that has the 8 speed and it's great! Smooth as butta.

Gangly · March 8, 2021

I have a 2020 5.3 8 speed with approximately 30k miles on the odometer and it shifts smooth as butter since day 1. 8 speed issues were resolved in late 2019, dont hesitate on the 8 speed, its solid now.

Jim165 · March 8, 2021

54 minutes ago, patrickjlindsay said:

Didn't GMC downgrade all of 5.3 SLT's to the 8 speed late last year? According to the Build and Price site right now, 5.3 SLTs get the 8 speed but 6.2 and 3.0 diesels get the 10 speeds.

I would get the 6.2 or the 3.0 just to avoid the 8 speed.

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Apparently is the case, but I thought they simply made the 10spd optional instead of standard with the 5.3. Thanks for all of the inputs, y’all..

TeamSaris · March 8, 2021

It was optional for a while. When I got my 21' you get 8 or 10 with the 5.3.

My 19's 8-speed was rough until they did a TSB on it, was smooth after that.

The 10 speed certainly makes the truck feel faster though.

f8l vnm · March 8, 2021

Cheap GM playing games with 3 different transmissions , SMH. ( meanwhile the 10 speed is standard for all engines including their base engine on the Ford side) I just don't get it

econometrics · March 8, 2021

I had a 2020 loaner with an 8 speed last year. It was much smoother than my 2/2019 build RST 8 speed.

I don't feel my 2019 8 speed is that terrible, but it does have some harsh or imbalanced shifts from time to time still (15K miles).

SilveradoRST · March 8, 2021

My 2019 RST 8 speed, build date 3/19 shifts smooth as well. Can’t feel the shifts. 1-2 is rough on cold mornings but apparently that’s a known issue and once it comes to op temp it is fine.

I don’t know if they will add the 2021 to the attached bulletin or if there’s a updated bulletin.

MC-10168176-9999.pdf

Z71RAD88 · March 8, 2021

This just came out today....

https://gmauthority.com/blog/2021/03/gm-to-replace-eight-speed-transmissions-in-some-2021-chevy-silverado-gmc-sierra-units/

dgstarr63 · March 9, 2021

I have a 2021 Silverado, 5.3, 8 speed, 4x4. At 500 miles I had hard downshifts into 1st gear at stop lights. It went away on the second day and was fine until at 1200 miles the same thing happened again and again at 1700 miles. Assembly date 9/30/1920 in Mexico. Do I qualify for a new transmission?

Z71RAD88 · March 9, 2021

46 minutes ago, dgstarr63 said:

I have a 2021 Silverado, 5.3, 8 speed, 4x4. At 500 miles I had hard downshifts into 1st gear at stop lights. It went away on the second day and was fine until at 1200 miles the same thing happened again and again at 1700 miles. Assembly date 9/30/1920 in Mexico. Do I qualify for a new transmission?

Not sure. Check out the article I posted. Maybe your symptoms are a reflection of what their talking about?

Gangly · March 9, 2021

15 hours ago, Z71RAD88 said:

This just came out today....

https://gmauthority.com/blog/2021/03/gm-to-replace-eight-speed-transmissions-in-some-2021-chevy-silverado-gmc-sierra-units/

Thats a completely different issue, but a new one none the less and great to know. Thanks for posting it up.

Gangly · March 9, 2021

13 hours ago, dgstarr63 said:

I have a 2021 Silverado, 5.3, 8 speed, 4x4. At 500 miles I had hard downshifts into 1st gear at stop lights. It went away on the second day and was fine until at 1200 miles the same thing happened again and again at 1700 miles. Assembly date 9/30/1920 in Mexico. Do I qualify for a new transmission?

No, separate issue altogether. Change out your transmission fluid with the updated version and see if that helps.