I have a 2005 3500 drw with 3:73 limited slip, 4x4, CTD. Auto!! I am wondering if I need to add friction modifier to the axle fluid front or rear with the stock American Axle setups. I am converting over to Amsoil severe gear 75w90. The oil change place said I need to use 75w140 for serious towing but i told him "show me in the manual!" He couldn't, of course. Does anybody know what the fluid capacity is on the front axle? Can I change it myself with out a torque wrench? any particular tightening sequence?