i have a 96 f250 4x4 5spd 351w and i have 3.55s in my truck and im running 265/75R16s and im planning on upping the tires to 33s in a few months. would it be a good idea to go to 4.10s now or after i get the the tires? thanks chuck

 

I'd get the gear swap done now instead of waiting, then you can tear up the smaller tires for fun! LOL

 

haha ok thanks what kinda gear oil goes in the diffs?

 

SAE 75W-90