what weight gear oil in rear end?

Like to change the gear oil in the diff. Curious what you guys are using
68 GS400 non posi

 

80/90

 

He has no posi Larry, may be a waste of money to buy the additive.



Bob H.

 

So - Larry is one of the "People of Walmart" we hear tell about?

 

At least he isn't buying the Super Tech for 4.18:laugh::laugh:

I've been running this stuff cause someone gave me a case for free!:grin:

 

Nope --Larry's hair is black.

 

I put 85/140 conventional oil in all of my rears.

 

I changed mine last year in my non posi skylark 71; if you do a search on differential fluid change you will see my write up on doing the service and what fluid I used. Hope it helps !
http://www.v8buick.com/showthread.p...id-Change&highlight=differential+fluid+change