When attempting to start my 92 L98, the starter energizes, but the drive pinion doesn’t extend far enough to fully engage the flywheel. It only spins and grinds against the tips of the flywheel teeth. This problem occurred with no previous warning or starting anomalies. The battery is supplying good voltage to the starter, and a starter rebuild shop said the starter was performing normally. All circuit connections seem to be clean, with good grounding at all appropriate points. Any advice on a possible diagnosis and cure will be sincerely appreciated.

 

Did the shop also closely examine the pinion gear engagement linkage? That includes not only the pinion (Bendix) itself, but the lever, solenoid core, pivot pin, and starter nose housing. Any wear in any of these areas can cause the problem you describe.

It's also omportant to shim the starter properly to allow the pinion to engage the flywheel without bottoming and interference.