Originally Posted by R_McAnulty
So picking up this thread. I’ll be going with 90 w mineral oil for the tranny.
Question, is the same oil fine to top up the rear end ? It’s a little leaky leaky ……

Thanks to all……..

I would not mix mineral oil with hypoid gear oil. It may be compatible, but I certainly wouldn’t take the chance of reducing the gear oil’s compression rating.

Geoff

1955 2nd Series 3600 235 cid, 4 sp. - Current
1979 Chevy K10 350 cid 4 sp -Sold
1955 2nd Series Wide Window 283 cid 3 sp - Totaled