[W126 Coupe] Starter Too

[Michael S Cosby]

My starter is having a problem  and I could use some advice before I go
to the trouble of changing it.  Every once in a while, it makes a
horrible grinding noise upon attempted ignition.  If I rock the car,
even slightly (in park) a few times it seems to "fix" the problem, until
it decides to do it again.  Is this the starter Bendix not engaging or
(horror) is it missing teeth on the flywheel?
Any ideas?
Mtnmike