I had a motor failure ~3 years ago and had to buy a new one, the electrical motor would not work. I ordered mine through Veurinks, got it next day but it cost me ~$900.
You might check with Visione Auto Mart, they carry a stock of used motors, you may get lucky but it will cost you.
When I did some more checking Power Gear does not sell parts, I was trying to repair my old motor. I took it apart, could not find any real problems so I put it all back together and tested and it worked fine, don't know what was wrong with it but I now have a spare motor for my front slide.
2002 Monaco Windsor 38 PKD
2005 Jeep Grand Cherokee w/5.7 Hemi