Most NAPA or Autozone parts carry it. If not go online at amazon or eBay and you can find it there. Get 8 quarts.

 

only need 7 qts (for both front and rear diffs) unless you have larger diff covers (maghytec)

 

Everything on my truck is still stock except the floor mats and front winter cover, though that could be considered stock because it's a dodge part.

 

i just did diff services today on mine. 7 qts of valvoline 75/90 full synthetic that had the anti slip already mixed in. buy a couple of cans of brake cleaner while your at it, with the covers off, you can clean out the diff (don't spray the cleaner down the tubes though, just the ring gear and carrier and cover), reinstall after cover is cleaned up and all garbage is removed (blue paper shop towels work great in soaking up stuff in the diff, just don't forget to remove it)