Re: Diff Oil Spec.

Posted by Owen_Dyneto On 2010/3/23 17:56:59

Packard recommended SAE90 in the winter and SAE160 in the summer. Most everyone I know with prewar seniors
uses a multivis SAE85W-140 which is available in countless brands, but usually only in 5 gallon containers. Note that whatever you select it MUST be of the EP (extreme pressure) variety which is required for hypoid gearsets. Typically we use the same lubricant in the transmission and steering gear box, so a 5 gallon container isn't really too much. I didn't bother to look up how much the differential holds, but it's probably between 4 and 6 pints but in any case you just fill to the bottom of the filler plug hole. PS - if you haven't changed the differential oil in the last 5 years or so, I'd strongly consider draining it, and maybe even flushing with a bit of kerosene followed by a bit of fresh gear oil before refilling. Inexpensive precaution, rear axle service can get expensive.

UPDATE - Per owner's manual (download it if you don't have it, its got some good basic information):

Differential - 6 pints
Transmission - 4-1/2 pints
Steering box - 3/4 pint