I did not put anything on my seals, just some Hylomar on the outer plates that retain the axle bearings.
Make sure the pinion nut is tightened properly if you loosened it for any reason. Use a cotter pin or safety wire unless it's one with a nylock nut. You don't want the pinion nut to come loose. Telling you what happens would cause me to have a very emotional flashback.
Don't forget the little cotter pin that sort of plugs the vent hole on top. You don't want the hole to close completely, though.
Good luck,