Im sure I asked this before but I cant find it. I am going to change my rear diff. today and wondering what to use, I have 75-80 syn. on hand. I do have limited slip and need the additive can I still run syn. in limited slip. thanks

 

I don't see why you can't use 75-80 synthetic and LSD additive. Sounds like a plan to me

 

that will work 80 wt is good and thick ... but like you said put a couple tubes of slip additive in forsure... use a new gasket or some rtv sealant because that synthetic will find a way to leak

 

Before changing the rear fluid, find and CLEAN OUT the VENT.

A plugged axle-vent will build pressure and force fluid through the seals.