I just used generic NAPA gear oil, and added a squeeze tube of friction modifier. Haven't seen any synthetic gear oil you could buy off the shelf around here. Might be worth a try. The last time I changed the gear oil (after 18k miles)it was very clean. There was some clutch material on the fill plug , which is normal.
royal purple with friction modifier already mixed in![/Q you can buy it in the store like that, with the friction modifier already in it, ready to go. how much do i need, how much does it cost. thanks