I used 87td's procedure on mine years ago. At the time I had the whole mirror assembly apart as it had frozen up from prior neglect (ahem) Thankfully the assembly is fairly serviceable as I recall. Upon reinstallation I had a make the firm but gentle adjustments to get things lined up correctly again. The little gears and motors are pretty tolerant of the procedure. It does sound some like things are breaking as the gears 'skip' over each other. In my case I had to go pretty far so it was like a zipper sound. Still working as it should today.

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1985 300D
The rest:
1957 MGA (comatose)
1965 Falcon (sleeping)
1966 E-100 (rust test in progress)
1976 Ford 3400 D Tractor (workhorse)
1978 Mercury Zephyer (5L playtoy)
1995 Isuzu NPR D (fetcher)
1998 Subaru Legacy (Spare)
2000 Toyota Sienna (School bus)
2008 Toyota Prius (Commuter)