There are a bunch of posts on the Vintage Forum on this - try a search.

What is happening is that the shaft is turning but the gear is not. The fix is to pull the shaft out of the gear, rough up the shaft with pliers, apply some Loctite and slide the shaft back into the gear. It is not a big deal.

Palo Alto Speedometer is the place to send it if you don't want to try this yourself.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe