I have experienced your problems, I changed out the gears, and I changed out the motor. The motor has a slip clutch in it. Since I had two motors, I mounted one motor on each landing leg and added another switch. Now I can raise or lower each leg individually and there seems to be a lot less strain on the motor. Hope this helps, PM me if you need any advice.
'05 Keystone Challenger TPK
'01 Chev 2500HD Duramax/Allison
Corgi "Pippin" & cat "Sundance":)