Rear end fluid

[JonZ71]

I've always ran 75-140 Synthetic. But either or.

 

[monstar_est87]

If you only had one wheel spinning then it shouldn't be a locker. Best way to check is to look at the RPO codes in the glove box. There's an RPO decoder list somewhere on this site that will help.

Ok will do... Thanks bratha...

 

[92k1500chevy]

Are they reusable?

Suppose to be, it's the same as their diff gaskets.

 

[monstar_est87]

O snaps, O snaps..! So i finally lookd up my RPO codes and...

Bam..! GU6-AXLE,REAR,3.42 RATIO 3.42R(GU6), G80-AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)
Autotuned... So wats the suggested rear fluid here..?

 

[ChrisAU]

O snaps, O snaps..! So i finally lookd up my RPO codes and...

Bam..! GU6-AXLE,REAR,3.42 RATIO 3.42R(GU6), G80-AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)
Autotuned... So wats the suggested rear fluid here..?

Regular old gear oil. NO ADDITIVES!

 

[JonZ71]

i put additives in my G80.. Never had a issue. Even did it in my 10b camaro. no issues.

 

[monstar_est87]

I think ill try wat mudwasp suggested... Pg2 post 14 - SAE 80W-90 GL5 (P/N 10950849).

 

[ChrisAU]

I think ill try wat mudwasp suggested... Pg2 post 14 - SAE 80W-90 GL5 (P/N 10950849).

Yeah....thats standard Dino 80W/90. $2/quart at wally world.

 

[Sparg93]

Let me clear up some misconceptions about Permatex Black - you can NOT use it with synthetic fluids (there's a post on GMC4x4 explaining it in a few more details). About two years ago, Permatex decided to tell everyone their Black gasket maker was not designed for synthetic fluid, only conventional. The synthetic fluid was shown to eat away at the RTV (but it took awhile to really damage it).

As you can imagine, when they announced it, they also came out with Permatex GEAR rtv...you can use this stuff with synthetic fluids.

Also, if whatever piece of metal you have in your rear does not call for Synthetic fluid or fluid with additives, don't use it (I made that mistake recently); it can cause slippage. Synthetic fluid costs a TON more so you'd be decreasing performance while spending more $$.

Hope this helps!

 

[Blue95]

No additives for the G80, it says in the service bulletin not to at all, I have Castrol Syntec Synthetic 75w-90 in mine now and I am about ready to change it again with 50K on the fluid.