Chevy RPO question

[Elk Hunter]

I got bit by the OEM rear differential cover catching a rock on the extended lip causing a small fluid drain and ended up blowing the rear axle.I wasn't aware of the issue till the Service Manager at Chevy told me to check on line, it's a known problem that GM won't step up and claim.
I'm trying to find a new aftermarket cover and skid pan. AEV shows a cover but states in for RPO code SU7. My RPO code lists "SU6-SU8 subaxle supplier". It's a G80 and RPO GU5 3.23 rear axle ratio.
This tells me that the AEV skid pan, is not for my truck, but per the RPO is it an SU6 or SU8?

 

[Stormin08]

poke around a bit inhere, there is a thread describing with pic of the 2 styles

 

[rascal71]

2024 trail Boss rear differential fix

2024 Trail boss, 3.0 Duramax, 10 spd automatic and 4WD (G80 SU7 Differential) I started looking thru all the old posts on issues Trail Boss Members had and found one that stuck in my head from PHXPHOTOG on a misadventure in Moab concerning rear diff problems. I too will travel to Moab this...

www.trailboss.org

 

[GETGONE]

AFE has aluminum covers that fit both styles. I put one on my 6.2L TB Custom.

 

[BigBlackie_'25TB]

I put a nice PPE diff cover on my '25 5.3L TB LT. Mine is a SU7 9.5 ring gear. This is the one I purchased.

 

[mrcolieman]

I got bit by the OEM rear differential cover catching a rock on the extended lip causing a small fluid drain and ended up blowing the rear axle.I wasn't aware of the issue till the Service Manager at Chevy told me to check on line, it's a known problem that GM won't step up and claim.
I'm trying to find a new aftermarket cover and skid pan. AEV shows a cover but states in for RPO code SU7. My RPO code lists "SU6-SU8 subaxle supplier". It's a G80 and RPO GU5 3.23 rear axle ratio.
This tells me that the AEV skid pan, is not for my truck, but per the RPO is it an SU6 or SU8?

I'm not familiar with RPO code SU6. The two axle manufacturers are American Axle Manufacturing (AAM) and General Motors (GM). RPO codes are as follows:

AAM axles were supplier A RPO SU4 front axle, RPO SU7 the rear.
GM axles were supplier B RPO SU5 front axle, RPO SU8 the rear.

RPO SU8 (GM) is the rear axle that has the low hanging diff cover and the AEV skid plate does not fit.

My 2019 Custom has the SU8 (GM) in the rear and the SU4 (AAM) in the front. A mixed bag but probably what was available at time of assembly at Fort Wayne. I built my own rear skid plate, allowing me to keep the stock cover. I thought about trimming the cover to fit more like the SU7 (AAM) rear but cutting off that little 90 degree angle from the bottom takes away the strength of the stamped steel and I didn't want it to eventually leak when I torqued the bolts down.

Here is the thread to this problem:

TB has serious flaw when off road

Bottom line: The rear differential cover is poorly designed and is easily damaged leading to a total loss of fluid when off road. The lowest point of your ground clearance is the differential cover, not the differential. The cover has a ridiculous lip that extends past the outside diameter of...

www.trailboss.org

Best of luck!
CJ