I had the same exact thing happen to mine about 3 years ago. 1985 300D Turbo, W123 I found a guy in CT, who is a dentist, that drills a hole and sets a pin into the gear thru the shaft. Cost $60, and that included shipping. I got SUPER FAST service, with turn-around within 24 hours. Mailed it on a Saturday and got it back on a Tuesday. Works PERFECTLY. Well worth every penny. Very impressed and it's a permanant fix guaranteed for life.