When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It's not really a posi traction, it's a torque biasing differential, it uses no clutch plates or cones and needs no special friction modifiers so regular gear oil works best, 80w90 should be fine.