The very used HO52 with 4.11s I bought had a bit of pitting in the ring gear. It's a little noisy, not a lot but annoying just the same. I originally filled it with 85/140 (as I recall), then after a couple hundred miles drained a quart and added a quart of Lucas. That helped but the rearend was still making noise so I added a small blue bottle of STP one of the original viscosity additives....better but not as quite as I'd like.

I think I'm going to drain the above cocktail out and try this, Swepco 203 Moly XP Gear Oil 250 wt./ISO 1000 1 Gallon (New XP Formula). It's used in lots of high hp transmissions and rearends. The moly additive should help cushion the ring gear and quiten things. We'll see.

Of course in a perfect world I'd change the ring gear and pinion, but that's not gonna happen.

RonR

RonR


1951 3600 with Clark flatbed, T5, 4.10 rear
1970 340 Duster
1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain)
1964 CJ5