I'm in the middle of a W201 project and I'm unexpectedly finding a difference between my '90 transmission and my '93 transmission. The '93 has a white plastic mechanism on the right side where the bowden cable attaches to the transmission, but the '90 does not. The problem is that this mechanism has a vacuum line going to it from a firewall vacuum solenoid, but the '90 wiring harness does not have a connector for this solenoid. Does anyone know the function of this mechanism and the vacuum line?