after
if you're talking about the shifter box, you can put it on before. i personally don't like to, i don't want anything to hang up on the tunnel or floor when installing.
if you ask 4 people this question you'll get 6.5 different answers. i've used the red hi-temp and just generic disc brake bearing grease and everything in between. dealer's choice. just make sure it's EP and heat rated. if you're talking generic white lith, then use something else.