So I recently inherited a JD 828(?) snowblower from my mother in law, worked great the first few days this snow season, then today as i was clearing some moderate to large snow drifts (light snow only), the auger stopped turning. I cleared the front out and made sure there was nothing freezing it up; in fact it spins freely when disengaged. When totally clear, it will spin when engaged, however when any resistance is applied, it once again stops turning. The 'blower' at the base of the chute is working normally. IMHO, the differential (if it can be called that) is shot, more or less, stripped or otherwise not in good health. But I'm the beginner here, and I'm open to any suggestions anyone may have on A. what it may be, and B. how to and how difficult it will be to DIY. Thanks!!