My truck is a 1965 F250 with the Dana 60 Limited Slip rear axle. I've only had the truck a short while and am changing the rear axle oil for the first time. The stuff that came out was thicker than molasses. The new stuff I put in that came from the local part store was a lot thinner. Here's what I bought:
Valvoline SAE 80w-90 Limited Slip. The bottle says "recommended for all hypoid differentials where API GL-4 or GL-5 fluid is specified."
Parts guy says this is correct for a limited slip axle, but I'm wondering if this applies to an old truck like mine or only to modern truck limited slip axles. Did I buy the right stuff?