I saw in your last post that you adjusted the stops as recommended by Lippert. Did you examine the actuator arm I referenced in my post? I know that if it's set just a little bit too tight, it'll destroy the gears. I adjusted mine after a few breakdowns and, for around seven years, haven't had a failure.
Another cause of gear failure is an operator error. If you are in a hurry to get out of the rig and put weight on the steps before they are fully extended, you'll run the risk of damaging the gears. Again, this always occurs just before the steps lock in place. Weight on the steps while they are extending puts many times the normal stress on the gears which promotes damage.