sorry for the stupid question but what is the grape juice? I think when I serviced mine last week I used a synthetic posi approved fluid I got at advanced auto parts. Don't remember the brand name but it was a good name brand seems like it was around $15.00 per quart. Is this grapejuice stuff better? I still have the front to change just waiting to get a few miles on the front before changing as I have not used it yet.
Beginning in 2006, the Front Differentials are factory filled with Synthetic, so you should already have the white cap.
Jperry, Grape Juice is the nickname for the GM Synthetic Axle Oil. The part number is 12378261 and retails for $27.55 per quart from GM. You can use this oil if you like, or any good synthetic 75W-90 or 75W-140 if towing heavy.
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