Tow Bars 71 Duster 318

How far is too far to two the Duster with a 904 transmission, with the drive shaft still connected?
I want to do a test tow on the car without disconnecting the drive shaft.

I found some information. The pump that moves the oil in the transmission is driven by the engine.........So if you tow it and do not disconnect the drive shaft, The differential will keep the transmission spinning but there is nothing to keep it lubricated (the pump will not be running)