1973 diff oil, running 3:73

[JD1973]

What gear oil should I use in my 1973 K10, the truck is all stock, but the cover is now leaking, I see 80-90 is what is reccomended, also How much is needed to fill the rear differential?

 

[Snoots]

It's about 2 quarts of 90 weight. If you have posi, don't forget the additive. Put that in first. Pour in the 90 until it just starts to run back out. Plug it and go have fun!

 

[SirRobyn0]

Yea, these rear ends are not to sensitive. Pretty much anything gear oil will work, but 90 weight or 80-90 is preferred. posi additive if needed.