The most common transmission failure caused by towing with the driveshaft spinning is failure of the pocket bearing where the input and output shafts meet. Unless the cluster gear is turning to splash lube around inside the transmission case, it doesn't take long for the pocket bearing to run dry and seize up. If you absolutely must tow without removing the driveshaft or the axle shafts, start the engine on the towed vehicle and let the trans spin at idle speed with the shifter in neutral. Another work-around is to overfill the transmission by a couple of quarts to submerge the output shaft in lubricant. My wife followed me 2500 miles from California to Tennessee, driving a 59 Burb and towing a Datsun 510 station wagon with the trans over filled. I was driving a Cadillac Fleetwood and towing a 3-axle backhoe trailer.
Jerry


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