The car runs very well and hasn't had any trans problems since owned by me. The fluid and filter are relatively fresh (last year) and the fluid appears clean and smells fine.
I have defeated the EGR valve and associated switching on the valve cover. I have also adjusted the VCV for full travel and since doing these things it has shifted flawlessly.
It has no Bowden cable, only the vacuum line and a wire (2 total) running to each side of the trans from the underside of the body.
Today it suddenly began upshifting very early regardless of pedal position and was winding up in 4th at 25mph. When I attempted to hold it in gear with full pedal it shifted back and forth from 4th to 3rd rapidly and repeatedly. I removed the VCV and it seems to be working fine-holding vacuum when closed and bleeding it off when open.
I took a drive with the vacuum totally disconnected from the trans and it made no difference in the shifting behavior (this may be the most telling of all symptoms from the searching I've done). Oddly, the car doesn't downshift when slowing down even with WOT at very low speeds.
It shifts fine when rowing through the gears "manually" with no apparent slippage or flaring. Also, now it doesn't "hunt" from 3-4-3-4 like it did earlier-it merely stays in the higher gear.
The electric kickdown switch seems to have no effect on the situation.
Open for suggestions. I will have intermittent computer access until Sunday night (8/1) so please don't be offended if I don't post until then.
Thank you in advance.
Chuck.

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".