I have an MTD 31A-3BAD729 snowblower given to me. The instructions say 05/2005 on them, so I'm assuming the snowblower's from about that time. The auger works fine. However, the wheels hardly turn when I left the unit up off the ground. They'll spin around somewhat. I can freely turn them as well when the unit is off. However, when I set it back down on the ground, there's either not enough power to move the blower, or it'll jerk forward a few times, moving just a few feet. I checked the drive cable, and there's definitely enough tension on the transmission. That works like it should. The drive belt looks almost new as well. The spring from the drive cable to the transmission and the outer gears are fine. I suspect the transmission is bad, but wanted to get other thoughts before dropping $130 on a 618-04296 / 918-04296B transmission. Thanks.