The toro self propel is really a one wheel drive system friction moves the other wheel I bet turning one way is easier than the other. Where did you get this idea????
Personal Pace is a two wheel drive system, simple drive gear attached to a common shaft, driving both wheels. If the wheels are not both driving, the non driving wheel needs to have the drive gear and/or key repaired. Toro Customer Support said not for hills??? If the hill is steep, no mower will go up on it's own. Mine goes up a 45 degree hill with some assistance. I'll bet you need to replace a stretched belt.