Look into Valvoline DuraBlend. Decent stuff. I end up changing my diff oil for one reason or another so frequently that synth makes no sense for me.
Another thought on that: synth does not protect from water infusion due to deep crossings, or from the accumulation of metal particles from R&Ps... frequent changes advised.
Nevertheless, if you pull my rear diff plug you will find red coming out. What does it mean if a guy has RedLine Shockproof laying around and is too lazy to go buy cheaper stuff when he is doing a reassemble at the last minute?
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.