Couple different problems here I think.

1. Don't seem to be getting into the turbo on acceleration from dead stop.

2. Then, the shift through the first two gears is smooth as silk. However, when shifting into fourth, it just kinds "slides" through the shift. Sometimes it feels like it just "falls" into the next gear. Fully depress the accelerator after going into fourth and it's a dog. No acceleration whatsoever. Then when it downshifts back into first, there is a heavy "clunk". The clunk wasn't there before we changed the modulator valve.

Have replaced the modulator valve on the transmission, as well as the shift actuator(?) that goes in behind it (reminds me of a syringe). Fluid and filter also changed.

Am wondering if there is a kickdown switch on the 83 300D Turbo? If not what part controls the downshift from fourth to third when slowing and gives a boost to the acceleration?

As usual, any insights certainly appreciated.

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Don
'85 500SL (Euro) - 186,000 w/a complete restoration and engine rebuild at 154,000
'95 C280 - 174,000