Is there any reason why I cannot flat tow a Z31 manual trans. with my motor home?

Even in netural,without removing shaft would turn torque converter,and fluid pressure,would build up ,this is what hurt,s the auto tranny,s,you would be fine,to remove shaft,but risk of damage by not removing could end up costing you a tranny.

the answer above deals with a auto trans--is there a reason that you can not flat tow a 85 300ZX Manual trans behind a motor home?

is there a reason why a manual trans 85 300ZX can not be flat towed behind a rv??

Still, is there a reason you can not flat tow a manual 85 300ZX behind a RV ?

Because the transmission fluid pump is geared to the engine not the driveshaft, so zero lubrications.