The motor is in the trunk, can be run with a 17mm socket.

Growling sounds like stripped gears or cable, the "gear" end of the cable is simply a wire wrap that engages the drive gear teeth.

A used drive unit is not big money, IIRC all of the 124 sedans use the same unit.

Opening the tip-up panel in the headliner, you can see backward to the cable end in the center-rear of the panel. Two 8mm-hex bolts I believe to take the cable end loose, pull the gray plastic knob out one notch on the drive assembly, and turn the 17mm-hex on the drive to run the cable out into the cabin, pull out once it reaches the end of the drive part.

Once the cable is removed from the drive, the cable can be removed/checked/cleaned and lubed/replaced and the drive unit is easy to remove.

The sunroof tip-up mechanism is a bit more of a clockmaker's task to repair and adjust, but the drive mechanism is IMO pretty simple.

__________________

Gone to the dark side

- Jeff