Oil for rear?

[mustangjoe87]

friction modifier lets the clutches slip. so the diff works correctly, i used valvoline 80w90 works great also i rebuilt my trac lok worth the 50 bucks at summit.

 

[jwzg]

Royal Purple is pretty good stuff as well. tain't cheap.

 

[Mavrick]

I'll be using RP 75w90.