Why Can't I Tow My Car With The Drive-wheels On The Ground?
You can......if it has a manual transmission placed in neutral or a four wheel drive vehicle with the 4X4 control shifted into neutral. Why this is possible with a manual transmission is because as the driving wheels roll, they turn gears inside the manual transmission and it self lubricates as a result of the gears spinning in the lubricant, which is then transferred to other parts. In the case of the 4X4, when shifted into neutral (the 4X4 control.....not the transmission gearshift) it completely disconnects the transmission from the driving wheels.
Should you tow a two wheel drive vehicle equipped with an automatic transmission with the driving wheels on the ground, catastrophic failure may occur. As the drive shaft or drive axles are turned by the wheels, they turn components inside the transmission. An automatic transmission is only lubricated when the engine is running, which produces hydraulic pressure that pumps fluid throughout to lubricate. If you don't lubricate it, you may damage your automatic transmission.
A vehicle driven a mile or two may not suffer extensive damage but we feel the gamble is not worth it. One of the very first things tow truck drivers are taught, is not to tow with the drive wheels turning with an automatic transmission.