Drian and Change Diff. in a '56

[luckyd]

what methods has anyone used to drain the diff?? Buick did not put a drain plug in as the manual says you
should not need to change the fluid. Somehow I do not think they thought 50-60 years later you might
need (or want) to. Would a hand transfer pump work, maybe thin the oil out,???????

 

[Canadian Buick Mogul]

I used a hand pump that comes with a floor mounted reservoir. The grandson pumped while I "vacuumed"!
Worked pretty good I think.
Refill with a squeeze bottle until overflow at the drain plug.

Canadian Buick Mogul