Rear Axle: Best Twin Traction axle lubricant

[Bob V]

After a five year search, I just bought a 64 Avanti R-1 with Twin Traction. I'm in the process of flushing/draining all the fluids and replacing with fresh. I understand the Twin Traction uses some bronze bits and I want to make absolutely certain I use a compatible lubricant. The factory workshop manual says to only use Studebaker Twin Traction lubricant but of course that isn't available anymore! Appreciate your advice!

Bob V

[RadioRoy]

Posi traction lubricant will work. NAPA stores and better parts stores carry it.

[Bud]

Many modern gear lubes such as Mobil 1, Amsoil and Redline have limited slip additives already included. There is also a limited slip additive that can be added to most GL5 gear lubes that will keep the clutches in the differential from chattering. I use Amsoil Severe Gear 75W-90 gear lube in my limited slip differentials and haven't had any problems with chattering clutches. Many people say that the premium synthetic lubes are too expensive, but how much is used and how often is it changed? Bud

[karterfred88]

Any modern "Limited Slip" additive will work. The basic design of clutch based limited slips hasn't changed much in the last 50 years, only the friction surface material. Newer ones are actually less tolerant than ours. Most FLAPS carry some form of it in stock, just use it even if the new hypoid says it will work with posi units, just to be safe. Worst case, you don't use it and notice some chatter on a hard turn at slow speed, you can always add it later.

[Bob V]

Thank you gentlemen!

[Xcalibur]

GM stores have the additive, in a pinch.

[Mike Van Veghten]

Most "all" modern (quality) differential oils are formulated for the various "limited slip" units available today, including the Dana style in the Studes of old.
I use Valvoline or Mobile 1 synthetic in all my cars, "posi or not.
An "additive"...is only required if you use a lower grade (read that cheap !) oil. Just read the information on the bottle of a good oil..!

Mike