I haven't done it on my x yet, but have on my RL. It uses ATF in the diff and hypoid chamber. Torque should be around 34lb/ft and you have to change the all 4 washers which are available at the dealer or through Tim.
Mike, Hollywood, MD
08 Aspen White Pearl/Parchment Sport/Ent, ordered sports running boards, cargo cover and tray from Tim.
06 RL PWP/Parchment, wood wheel/shift knob, spoiler, b/u camera and mudguards.
Retired 01 MDX Prem/Navi and 03 Navi/DVD