i have a leaking pinion seal and i am going to take it out to my buddies house on sunday to replace the seal. now, at work we use exxon synthetic 80w-140 gear oil in our rears( eighteen-wheelers). can i top off my car with it just to drive it like 30 miles to my buddies house? i live in apartments and we cannot work on cars over here, so i just use my buddies shop. i noticed richmond sells a 75w-140 gear oil and thats why i was wondering if its ok to use it. can it be used all the time??? thanks

 

It should be OK. You could probably use that as the fill fluid, it would just cost you some RWHP and gas mileage. But it won't hurt anything.

 

how does it affect mpg and rwhp? thanks for info btw, we have several 55 gallon drums at the shop. good to know i can use it. btw, do i fill it up till it comes out of the plug hole?

 

Yup, that's what you do.

It's thicker, and doesn't lube as well as synthetic in particular, so you just end up with more loss in the driveline. The motor does some extra work that doesn't make it to the wheels.

 

My posi has been acting up and not locking up when going staight. I was wondering if i'm low on gear oil in my rear. What weight should i fill it with? I live near cincinnat ohio so its about 50-70 now, and will get up to about 80-90 over the summer, if temperature matters.

 

i think 75w-90, but i am not sure