I have 6 cats and 3 litter robot 3 open air machines. They get LOTS of use, and over the years, I have become quite proficient in repair. One of the units began squealing loudly when cycling. Upon disassembly, I found that fine litter dust had worked its way into the gear box through the small holes in the motor housing. As you can imagine, this did a number on the gears inside. This new replacement motor assembly comes with a plastic slip on dust cover over the actual DC motor assembly. An excellent improvement! Follow the video on the Robot Shop website for step by step instructions on replacement. 20 Minute job. Quick and easy!