Did you replace the starter or just the solenoid assembly? If the starter, you got a bad rebuild. It happens. If the solenoid only, well, you probably would have been better off replacing the starter. Hurt my wallet, but I went with a MB rebuilt starter when I had to do the starter last March on daughters '83 300D. Hers had the same problem. Hasn't missed a beat since. If you did the starter, is it still under some sort of warranty? Man, I hate taking that thing out on the 5cyl turbos.