Thanks again to all who responded. Got it jacked up from the rear for the first time. Found that PO's had dented the frame to heck and back. Fortunately it was before the restore 12 years ago because the paint on the frame is fine. Everything else I could see looked good.
Then I started the job of checking the rear gear lubricant. The 4' garage drip tray under the rear of the car has about a half cup of gear oil in it.
Typical story. Found the plugs. Drain plug has a drip of oil hanging from it. But wait a minute! The plugs take square sockets! Hmmm, wonder if my 1/2" drive will fit. Nope, too big by a hair. Wobble 1/2" extension sorta fits but pops out when I try to turn it. Afraid of damaging the nut. OK, off to Home Depot for square sockets and to pick up some vinyl tubing for getting the goop into the pumpkin. Off course, Home Depot used to carry square sockets, but they don't anymore. Only vinyl tubing that fits the nipple of the gear oil bottle comes in 20' lengths. (Anybody need 17' of vinyl tubing?)
Two Sears stores later and still no square sockets. Of course, a customer at the second one told me he just sold a set at a garage sale for $2. Bought a 1/2" extension for $8 and ground and filed it to the 11mm needed. Works like a charm. But the gear oil is almost completely full. Had the car on a sloping driveway so it was almost level when I jacked the back. Mechanic who checked it last works without a lift and must have filled it with the car jacked on a level surface. Squirted in a couple of ounces, most of which it regurged back onto my driveway. Tried not to think about why I did this in the first place.
Four hours after starting, I'm done. Glad I don't have to make a living working on these things!