Park the snow thrower on a flat surface. Detach the sparkplug wire to ensure against accidental startup. Using a screwdriver, detach the belt cover, located in between the engine and the discharge chute. Remove the chute gear cover, located near the top of the discharge chute. Turn the discharge chute to the left when you are standing in the operator's position.
Remove the hairpin that connects the discharge chute rod to the chute rotation lever. You may need pliers to pull this piece away from the assembly. Push the discharge chute forward. You may also have to remove the spring pin from the chute crank. These tasks will open up enough room between the discharge chute and the pulley assembly to remove the attachment drive belt.
Remove the traction drive belt. This belt looped around the series of pulleys closest to the main engine assembly. You may need to turn the engine pulley in order to help unwind the traction drive belt from its pulleys.
Install a new traction drive belt in the reverse order in which you removed the old belt. Replace the attachment drive belt in the reverse order in which it was removed. Reinstall the pins connecting the discharge chute.
Reattach the belt cover and the chute gear cover. Attach the sparkplug wire. Test the machine before the next snowfall to ensure it is operating correctly.