I just purchased the car with 157k miles. It has been relatively well maintained but, there are some shifting problems. I need some guidance with trouble shooting and resolution. The situation is this:
1. No leaks, rattles, sqeeks, etc. Fluid is clear and doesn't smell overheated.
2. When flooring the engine from a stand still the tranny shifts firmly at the shift points.
3. But, if accellerating at a leisurely rate, the tranny will allow the engine to overrun and slowly shift from second to third in about 3 seconds. The engine will race for the shift period. Shifting into high is soft but the engine doesn't race. Also, if flooring the engine for downshifting...it doesn't downshift.
4. Lastly, when shifting into reverse, the tranny takes about 3 seconds again to engage. But when engaged it is firm and doesn't slip.

Any thoughts ideas or procedures to trouble shoot would be greatly appreciated. Thanks.

I beleive the reverse situation to be about normal.

The other problems sound like a vacum problem, or possibly a need to have the transmissin modulator replaced or adjusted.

Thanks for the reply. I can't find any tech data on the tranny. Is there any procedure or specific tests that I can perform? I perform my own work until it comes to the injector pumps and injectors. I have tools and some test gear along with a portable vacuum system.

Again, thanks for the response.

On the side of the transmission is the modulator. It has a rubber cover and under that is a T key used to adjust shifts. It should only be adjusted in small increments. Turning clockwise makes the shift softer and counter clockwise hardens the shift.
This is how it is on a w126. Hopefully someone will chime in to confirm movement of the T key.

There is an elaborate write-up/thread going over at the other Benz forum. It addresses how to get these cars shifting their best.

I'm new at using the threads. How do I get over to the thread you mentioned.

HOw do I get over to the thread you mentioned?