The part is around $30 and it took my mechanic a 1/2 hour to install the modulator and test drive the car. Not a big expense IMHO. FYI: My car, a 1987 300E, has 113,000 miles on it. Though I didn't do the repair myself, it seems like a fairly easy fix. The valve's location is very accessible if you put the car on ramps. It's on the tranny housing on the driver's side.......there's a vacuum hose attached to it. I'm not exactly sure though how the valve attaches to the tranny, maybe it's a non-threaded, twisting type mechanism. You may want to ask one of the many very informed people who frequent this site.