Hey guys, I'm replacing the oil in the diff case, but I was curious as to about how much I should use. I'm ordering some Royal Purple Max Gear Oil. I've heard great things about it so I want to try it out. Do I only need about 1qt or should I expect more?

Also, I'll probably put some in the other cars in the house, (im trying to squeeze all the performance I can out of my 00 V6) and then our F150 makes funny noises when it shifts in and out of gear.

 

Your differentials probably hold about two quarts each. After draining all the old fluid out, just refill until the oil starts to run out the fill hole on the side/end (depending on differential) of the differential.