Help identifying which axle

[Atlas]

I scanned the QR code on my door sticker which does not appear to contain supplier RPO codes for the axles. It confirms GU5, Axle ratio 3.23 which I already knew, but I'm trying to identify who made the axles (GM or AAM) so I know what fluid to put in when I do post- break in maintenance on them. There are no SU_ codes listed which I read in other threads may identify the axle supplier.

 

Any ideas?

[AJMBLAZER]

You have to get the full RPO code list from GM customer service. It will be listed there. 

[Atlas]

Thanks. I emailed them and they provided me the full list of RPO's/build sheet for my truck. SU4 and SU7, so, AAM axles on my '20.

[Adamace1]

There's different fluids for these trucks? Like as in my 2021 and somebody else same 2021 would use a different fluid in the rear and front axel?

[Z45]

GM released new gear oil specifications for the late 2020 and 2021 model year pickups that now call for DEXRON Low Viscosity 75W-85 gear oil (GM part #19365814) and GM Synthetic Gear Oil (part #19300457 meeting GM Spec. 9986375).