Packard Forum Index » Post-War (1946-54)

What weight oil do I use for the transmission and overdrive unit for 288 cu in engine?

Packardwagon; The quick answer is: mineral gear oil, known as GL-1, but which weight has a bit of a back story.

In the website’s Literature Archive, you will find a User’s Manual for your car, and within there will be a lubrication chart that contains call-outs on the various lubrication specifics. Over the years you should also note that both 90 and 140 weight oil is recommended. In the 1942 Clipper manual there is additional insight that 140 weight is associated with warm weather, 90 weight for cold weather, and 80 weight for extremely cold weather . . . however in the very next sentence following the viscosity recommendation’s is a statement that the transmission oil should be drained and refilled once a year, preferably in the Spring. Later manuals make no mention of the 140-weight oil, but do mention switching to 80W only if difficulties in shifting are encountered.

I personally use 90W GL-1 in the transmission and overdrive year-round.

dp