My wife got our 97 4WD Explorer stuck in a snow drift on our long driveway (while in 4WD High), and I don’t know what happened next other than eventually a neighbor came by to help, snow was shoveled out from underneath the car, it was pushed back on the drive while in reverse, and then was driven in reverse back up the driveway to the house. The next day when I went to drive it, the was no engagement of forward gears with the shifter in Drive or 1st, but it would engage in 2nd gear. Anyone have any idea what happened, and whether this means a new transmission is now necessary?
The first thing you should do is check the level and condition of the transmission fluid. If the fluid is low, that could be the problem.
Any oil in the snow? You could have torn off a trans cooler line.