Its funny that you mention the vibration issue, as I have added a rack damper from a 300dt to the IP and turned up the coarse idle screw a bit and the vibration seems to be diminished, but not gone. I need to adjust the IP some more as the engine "hunts" at idle. I hope to be putting the 5 speed back in soon, and will be trying an auto tranny mount instead of the manual mount to see if it helps isolate the tranny from the body.

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1998 Mercedes E300TD

1983 Mercedes 240D Turbo, 131bar injectors, Cosworth intercooler and 63' Ford Falcon radiator, Ardic Parking heater, Headlight wipers, Best 38.6mpg.

1973 Saab 96 Rally Car, 1.8l V4 with all the race bits

Try backing out the rack damper and see if the hunting stops. It is normal for it to hunt a little when it is cold and warming up, (30 degrees F weather), but once warmed up it should hold a constant idle speed.

With the engine running, warmed up, and hunting, back out the damper and see what happens, (hunting reduces, engine starts shaking etc.). If the hunting stops, slowly turn it back in. You will feel it touch, then give it 1/8 to 1/4 turns at a time waiting 30sec in between to let things settle out after the adjustment. Keep going until the engine stops shaking, or it starts hunting.

If it starts hunting before it stops shaking, you will need to back off the Course Idle adjustment, ( Idle Governor Spring Tension), a touch, (try a 1/8 turn), and repeat the damper adjustment. The Rack Damper is putting additional force on the rack, which has the effect of increasing the Idle Governor Spring Tension.

In regards to the vibration, what condition is the anti vibration mount that is located under the engine, between the engine and bell housing? I was thinking of adding one to my 300D 4-speed before I sold it. Not sure if the extra connection would dampen it enough or not.