Re: Differential Fluid Change
AWD will have a rear differential yes, and it will have a seperate drain and fill plug (so you can check the level from here, the fill plug)
Pretty straight forward, just drain (90 weight oil is very thick so the warmer the differential temp. the better) and then fill right up to the fill plug.
I'd check with your dealer tech (mechanic) if a diff additive is required for your specific vehicle. Some do some don't.
Manual doesn't indicate anything? Even under the Specifications page? Recommended milage should be under the Maintenance section? No?
If not, your GM dealer parts counter will know what type and how much approx. it will take to fill so that you have enough. Usually sold in 1 quart bottles or 1 gal jugs depending on the dealer.
Service Dept. can tell you what GM recommended milage service is.
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