BenzWorld Junior Member
Date registered: May 2011
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I have a 1979 450SL with about 160k miles. Transmission shifting troubles.
I replaced the vacuum modulator, and took the car to a German car shop to have the modulator adjusted. Prior to installing the new modulator, the car had shifted fine; I chose to replace the old modulator at the time I had the car apart while replacing flex discs, trans. mounts, and carrier bearing.
The shop charged me $250.00 for the job. When I started to drive it home, it shifted extremely hard from first to second at about 25MPH. If I was "easy on the gas, it didn't ever shift into 3rd even at 45-50 MPH unless I took my foot off of the pedal just a bit. I took the car back to the shop immediately. A technician gave it a test drive with me, and - even after the tires "chirped" while shifting from 2nd to 3rd - said, "That's the way it's supposed to shift."
I find that hard to believe. The shop is going to readjust the modulator at no charge, but they were upset that I asked them to make it shift softer and sooner. They cautioned me that if they adjusted it, they couldn't be sure how it was going to shift. I replied that that was why I hired them; to adjust the modulator so it shifted like a quality car (as it shifted prior), not a dragster. I also felt that shifting so hard would be difficult on components such as the flex dics, and engine and trans. mounts.
Am I out of line, or is it the shop? This is the first 450 I've owned, and I've had it almost 15 years. I've never known a transmission to shift so hard and late. Is the way the shop claims the way a 450 is really supposed to shift?