55 years ago I found my rearend was low of fluid, got some black thick 600w in a quart metal can. It was in the fall a cool, how do I get it in there, found a long hose a funnel and warmed the can on the boiler. Stuck one end in the diff, ran the hose up to the spare tire added the funnel. Poured the warmed black 600w into the funnel and then waited for ever for it to flow down into the differential. Dumb teenager had more time than money LOL