Looking for insight into a transmission debacle. My wifes '83 300CD was not shutting down. After a few tests with my vacuum pump, I ascertained the shut off valve and the vacuum modulator were faulty.after replacing the modulator, I backed the car out to see if it needed any adjustments...upon putting the shifter onto drive...it did nothing, same with reverse, although I backed out of the driveway with no problem. The wife says the car was shifting fine....Any suggestions?? The car will not engage into any gear now. Could a clump of grease or debris have gotten down into the valve body?? Any thoughts would be appreciated. Thanks! Dave