I'm buying a rear from a gut on this board in a couple weeks. It has aprox. 60k on it. Just curious if I should bother changing the differential fluid before I put it in the car? If so, what kind should I use? Some kind of limited slip additive also? I want to make sure everything is kosher before it goes under the ride. Thanks

 

peace of mind says change it and add GM limited slip additive, not sure on the part# tho. its cheap 5 or 6 bucks
if its an Eaton posi dont use synthetic oil

 

How come, I don't know much about rear end internals so any info would be good to know. BTW the seller put a MAC girdle on it so I'm assuming he'd have to had changed the fluid during that swap, just not sure how long ago it was. Thanks

 

like i said, IMO it just gives me peace of mind and a point to start from for when the next fluid change comes around!

 

Ok then what about the no synthetic's with Eaton posi?

 

the synthetic oil is to 'slick' for the clutch material.....synthetic oil and Eaton= death to the Eaton
its more technical then that but i am not the one to get into it!
its recommended by Eaton, Moser and Strange to use standard nonsynthetic gear oil when using an Eaton posi dif.

 

Ok I was assuming something along those lines. Thanks for the info, it's good to know.