Towing Std. Shift RWD Car - Unhook the driveshaft?

The tranny is not the original.

When my son owned the car he drained the fluid and replaced it with a slick 50 product. He was not aware that the correct fluid was automatic transmission fluid. 1,500 miles later the transmission was toast.

My main concern about dropping the drive shaft was whether fluid might leak past the seal in the tail shaft, with the yoke pulled out and the car being tilted upward. But I could work around that.