Got a question concerning a self-propelled (rear wheel) Toro Super Recycler. The rear wheels over the years are becoming bald and spin when I engage the drive. Can the front be swapped with the rear or is there some special gears or something on the rear that works with the drive unit? I don't see anything obvious to look at it but figured I'd ask first. There's got to be something there that works to engage the wheels to move but have no idea if it's compatible with the front.