So I tried to install the diff cover and it leaked tried to take the lazy way out. Well looks like I will have to pull the cover and change the oil. The prob is when the cover goes on it blocks the fill plug how the hell do you get the fluid in. Seems like a s**ty design.

second question is what weight gear oil should i use and how much for each. d30 front and d35 rear as well as the T case.
97 Xj 4.0 32's stock gearing DD with some offroad

 

Yea I had the same problem with the dana 30 rough country diff guard it is a poor design for sure I trimmed some of the metal off the part that blocked the fill hole.As for gear oil 80w90 is what is in mine good luck with the poorly designed rough country diff guard.

 

i dont have the rough counrty diff guards .but what did work for me . was a push pump that screws onto the the bottle ,then just pump it in .so the question is will the hose of the pump fit in the hole behind the cover? might be worth a shot

 

No that wont work because you can not get the plug out