changing front and rear diff fluid in 2008 sierra

[catfishchris26]

I have a 2008 sierra SLE z71 4wd extended cab. I want to change the front and rear diff. I called two dealerships and they confirmed through my VIN I have a limited slip in the rear. I haven't' been able to find how much to add or what kind or how much of additive to use if I need one, which I think I do need one from what I've researched. Anyone know what the capacity is of the diffs and how much additive to add in the rear? Thanks for any help.

 

[buckwild27]

http://www.ws6project.com/user_stor/catalog/product_info.php?cPath=235_79_529&products_id=2250

 

[buckwild27]

The whole bottle of additive. The 8.6" takes 2.15 quarts and the 9.5 takes 2.75 quarts