If the gear shifter moves, but the blower does not change out of reverse, something between the shifter and the friction disk has either come loose or snapped. If the gear shift will not move, do not attempt to force it. Placing extra stress on the shift rod or shift arm can lead to snapping or bending and a more costly repair.
The shift rod is the long piece of metal that goes from the shift handle down to the shift arm. Check to make sure the rod is not bent or jammed. If you were operating your snow blower when the problem started, check for any ice buildup on the rod or in the slot surrounding the rod.
The shift rod ties into the shift arm, which runs horizontally between the rod and the friction disk inside the snow blower. You may need to set the unit up on its auger in order to gain access to the shift arm. If the rod and shift arm are tied together and have not snapped, the arm should be functioning properly.
The friction disk is the part of the snow blower that actually changes gears. The friction disk can become rusted and stick to the drive plate, preventing the unit from shifting gears. Remove the bottom panel on the snow blower and spray the friction plate with lubricant. Allow the lubricant to set in for a few hours and attempt to shift the gear. If the disk still will not move, contact a local authorized service center for Toro snow blowers and inquire about ordering a new friction disk.