What is the problem with our 1983 Mercedes 300 TDT shifts which shifts quickly to Top Gear with no slippage and works fine if manually shifted moreover all power door locks work well?

Answer 1

The vehicle shift points should change based on throttle position. Partial throttle will give closer shift points where as full throttle should give longer time between shifts. A few things could cause shift problems, but if they just happened all of a sudden than I would suspect the control pressure cable.

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If you look on top of the valve cover you will see a cable with an acordian type rubber boot over the end. That cable runs down to the tranny and is critical to the shift points. The ball end pops off the linkage and you will see a screwable plastic adjustment where the housing mounts to a bracket. I would guess that the cable end popped off the ball or the cable is broken.

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Adjusting the cable is simple.

1. Pop cable end off ball.

2. Push cable end first to the rear (towards trunk), then pull carefully forward (toward oil cap) until a slight resistance is felt.

3. In this position, hold the cable end above ball.

4. Adjust control pressure cable control at adjusting screw so that the ball socket can be pushed free of tension on ball head.

NOTE: The manual only allows 1mm of pull after adjustment, and no slack. That is how critical the adjustment is.

Hope this helps.