Differential fluid change w/ G80 + oil capacity

[E_S]

I want to change the differential fluid front and rear on my '04 Tahoe w/ RPO G80, and I've understood the locking rear makes for certain types of oil.

The Castrol Europe webpage states the oil "SYNTRAX LIMITED SLIP 75W-140" as the correct one. Can anyone confirm that this oil can be used?

And - how much oil do I need to do the front and rear diffs?

 

[Sasquatch]

My manual said that the rear diff takes 75w-90 and the front takes 80w-90.

I used 75-90 in both. The rear takes 2.75 quarts and the front takes 1.8 quarts.

 

[E_S]

Thanks! Then I'll buy 5 quarts.

 

[E_S]

Mission complete! After 110k miles..

Transfer case: Oil was dark, but not too bad. Refilled with the blue GM stuff.

Front differential: Oil was kinda milky, obviously some water had gotten in some time. Refilled with Mobil 1 75W-90.

Rear differential: Oil was brown-grayish. Replaced that bolt in there (old one wasn't too bad) and refilled with Mobil 1 75W-90.

Transmission: Oil looked fine, but probably old. Replaced filter and refilled with synthetic Dexron III.

Power steering: Sucked out as much as possible using a turkey baster-lookalike, started, repeated, started, repeated again. Old oil was dark. Refilled with the GM power steering fluid.

And then a test drive: Transmission shifts smoother, steering smoother and the truck feels like it does not bind as much when doing tight turns on pavement (2WD only, of course).

Conclusion: Well worth the $300 spent on various oils and gaskets. (yeah, stuff is expensive here!)

 

[Goodinblack]

Is there a gasket available for the rear end?

 

[E_S]

Yeah, I just went to the dealership and asked for one, and got it. Think it was about $20here in Europe, probably way cheaper in the US. Was told to use a little RTV in addition to the gasket itself.

 

[Goodinblack]

Good to know. Thanks

 

[Z-56 Hoe]

Goodinblack yes they are about $8.00 for the Dealerships here in the us.

 

[ez__rider]

is it correct to fill the differentials (front and rear) to the bottom of the fill plug, or to a level lower than that...? I have the Haynes manual, and it actually says both in the same paragraph.

 

[01ssreda4]

I fill till they run out the hole. It should be pretty obvious because the fill hole should be about midway up the housing...