If you tip it up on the bucket, and remove the bottom plate, what do you see when you move the shift lever between forward and reverse?
The rubber friction disk should go past the center of the spinning metal disk, to the left side of the metal disk, and the right side, as you move the shift lever to the extremes.
Is the shift linkage connected properly? Is the transmission adjusted properly? Your Service Manual should explain how to adjust the transmission. The Owner's Manual may as well. On mine, I didn't even have to remove the bottom cover to adjust the transmission. If it's easy to adjust on yours, you could even try that first to see if it helps.
You can download manuals here:
http://apache.ariens.com/cgibin/ctrg0005?SESSIONID=0.2145817532233396&Site=ARIENSS
This message was modified Feb 9, 2015 by RedOctobyr