98’C280 V6: Ticking vacuum/air valve solenoid? P#0004701593

[MarkC]

98’C280 V6: Ticking transmission vacuum regulator solenoid?

It’s been ticking for a while, and the noise comes and goes. The part number is; 0004701593 and I know it’s a solenoid (two wires to operate it) valve with two ports for air to enter and to exit. It is attached to the left, in front of the fender, near the power steering pump. It has the word 'MOT' in white on the top with a clear silicon plug over some adjusting screw I'm guessing. One of the line ends go to near the throttle body and into a tube to the intake (so then I assume it controls the flow of engine vacuum to something). When there is no power to it (out of car), the solenoid valve is close, allowing no air to pass through it (the tubes). I believe the other end goes to the transmission (but this is not confirmed). I called the dealer parts, he didn’t know what it was for, just that it was a valve. Anyway, anyone know exactly what part this does and the possible consequences of driving the car with it clicking (meaning it is not staying open)?

Any info would be greatly appreciated
Thanks,
MarkC