tomkanpa wrote:
It has a gearbox that is powered by a belt from the engine. It doesn't
appear that the belt is slipping. And the arm that engages the gears
moves. Yet there's no power to the wheels. Well, I take that back. On
a level driveway, it will pull itself along at a slow pace. At the
gear box which is part of the axle "jumps up and down." And with the
engine off and the gearbox engaged, the front wheels are locked as if
everything is engaged.
Any ideas on what the problem is?

The worm wheel on the driven axle has worn out. The lever slides the
clutch dog(keyed/splined to the axle) into the worm wheel, which is in
constant mesh with the worm gear.

It's not too bad to repair. All the parts are available at

http://www3.sears.com/

Pack the gearcase well with Lucas Red 'N Tacky #2 grease when reassembling.

Rob