Power seat issue - not motor, not cable.

[JimZ]

So, giving up on trying to fix the ignition lock (I just cock the wheel before pulling the key out - works for now until I have $$ to fix) I turned to my power seat problem.
When I bought the car, the drivers seat would not move front to back. The mechanic said it was something with the runners being slightly off, and when I picked up the car it worked...for about a week. I called the mechanic to find out what he did to fix it and he said it needs a new cable. I bought the cable and put it in this weekend. Didn't work. I hooked it up to a drill and watched the gear spin, but the seat didn't move.
I can hear the motor when I hit the button, and the seat cable is new. Turning the cable with a drill spins the gear but the seat doesn't move. What else could it be?
Luckily for me I had moved the seat all the way back before it stopped working, but my 5'2" wife hasn't gotten the chance to take it for a spin yet. So, for her, what should I try next?

[sixto]

The W140 has stupid nylon gears between the motor and rack. I'm guessing the W126 has metal gears but maybe they get stripped too. Set the seat as high as it will go and look for the motors and gear drives. Should be mostly accessible. Put a sheet over the carpet or remove the carpet because there's some nasty grease in those gear drives.

Sixto
93 300SD