vitara transmission reverse

we towed the 2002 grand vitara 475 miles on a dolly, set up in nuteral as per the dolly instructions. Arriving at the destination, the car would not reverse to back off the dolly. Pushed it off, drive works well, all forward speeds work well but reverse still will not engage. is there a linkage adjustment or do I have a bigger problem?
vehicle was towed with rear wheels down and rotating, tranny in N