Sierra 5.3L AT4… 6spd versus 8spd, which one?

[Jchaffin20]

I’ve settled on this being my truck, but wanted to hear thoughts on these two transmission options. 
 

Thanks all!

[Tigerwitha88]

Had a 6sp in a 2013 5.3, now have a 8sp in a 2020 5.3. No comparison, go with 8sp, faster acceleration.

[redwngr]

Getting a '21 (or 22) AT4?

 

Isn't the 10 speed standard on AT4 now?

[dgstarr63]

Get a 6 speed or a 10 speed. The 2021 8 speeds are still having rough shirt issues on some trucks (mine included). GM is ignoring the problem and is of no help.

[Matt G]

Have to agree with the above. My 8spd shifts rough occasionally.  Nothing that I can’t live with but if I had choice, I’d have gone with 10 spd.   Inventory levels were low when I bought mine 

[blckblt]

Out of all three options from GM I would only go with the 10 speed.

[Elevation X31]

My 2020 with a 5.3 isn't even an AT4 and has the 10 speed, although won't be offered in 2021. 

https://gmauthority.com/blog/2020/12/2021-gmc-sierra-5-3l-v8-and-10-speed-automatic-combo-axed-from-sle-and-elevation-trims/

 

Edited June 15, 2021 by Elevation X31