2006 E320CDI Transmission shifting at much higher rpms under very light acceleration.
 

The car has been near perfect the last 8 years. The transmission now under very light acceleration shifts 1 to 2 at 2100rpm, 2 to 3 at 2300rpm and 3 to 4 at 2900rpm.
By briefly moving the shift lever to the right I can shift up earlier and into the high gears including 5th on the highway.

Transmission history:
Apr 2016 91,000km 56,875Miles Dropped the pan, cleaned, new filter and gasket used Shell 134 the approved fluid.
May 2018 138,700km 86,687miles removed drain plug and filled with Shell 134.
Aug 2023 203980km 127,487miles removed drain plug and filled with Shell 134.
The transmission color was and always is a bright fresh red.
March 4 2024 did the transmission plug and immediately upon the test drive the high shifting commenced. I noticed the plug was leaking when I changed the engine oil.
The highly reputable transmission shop feels that all the gears are there and that some unknown sensor is telling the transmission to hold the car in gear as though I am accelerating aggressively when actually I am using only the lightest of acceleration.
Only stored code is for abs and the abs works perfectly with no problems (likely set in winter with low battery voltage).
Current 218000km 136250miles.
Anyone experience this, ideas please.

Haven't experienced this...look forward to hearing the resolution.

Would a good next step be to do a full service, including replacing the filter?

I am interested in your situation because I have basically the same service regimen: longer full service intervals, with periodic fluid replacement in between. On mine, last full service done at 123k miles. I've replaced fluid at 145k and 161k....will do again at 175k or so. I think I may try to get to close to 200k like this and then do not only full service but also conductor plate replacement.

Search on resetting the memory for the transmission back to factory specs. Look for a video, it involves cycling the ignition key/fob and the accelerator pedal in a specific sequence.

Remove the transmission plug and see if one, or more, of the 13 pins are bent or misaligned.

Could have easily been damaged when you replaced the connector plug.

1) the transmission fluid of my 2006 CDI is always brownish black and quite thick. It seems to have graphite content. Not fresh red like yours. My CDI has 331k miles and shifts perfectly, so I don't know why the fluid is brownish black. I googled and other users also claimed the color is brownish black.

2) did you say your transmission plug has fluid or leaking? If it is then you have a problem with your conductor plate. It definitely can cause the problem you are experiencing.

Changing conductor plate is $$$.

Quick update
 

Hi TimFreeh: I always go to the last item worked on to troubleshoot. Today I disconnected the transmission plug. It had a bit of transmission fluid on it. Using a mirror and flashlight it appears as though all the pins are there and straight. I flushed the external plug several times with an electrical connection cleaner and then used DeoxIT to additionally clean and lubricate. Then I sucked it in and out with the leaver several times and re-cleaned. No change on the test drive still shifting high and late on the very lightest of acceleration.

It is almost as though the emissions system thinks the car is stone cold and holding it in the gear longer to heat up faster and reduce emissions.

shertex: Over the years I have enjoyed your posts. My understanding about transmission fluid is that the biggest benefit is the first fluid exchange. It replenishes the additives and removes the "crud" from the old fluid. I still do additional drain and fills for peace of mind and because they are easy and relatively inexpensive.

Sugar Bear: In have considered a transmission reset but am afraid that it may reset to the higher shift points. I see a bit of a danger. I also have a belief that the transmission learns and continually adjusts to the last 200 shifts? I could be wrong?

ah-kay: Shell 134, the recommended fluid comes out of the container a bright red and mine is still a bright red. I believe that is the way it should be.

Going to an Indie Monday for a full diagnosis.

As you pointed out it seems unlikely that the transmission failed immediately after you replaced the connector - its probable that something in that replacement event is causing your issues.

The 722.6 is totally dependent on a myriad of electrical signals/data for shifting decisions and implementation, I'm still betting one of the speed sensors or modulating pressure transducers isn't seeing the electrical data it needs?

Hopefully your indie will have scan tools that can talk with the EGS controller for the transmission - there's lots of info to be had.

Does this have a kick down switch under the pedal? It could be stuck. disconnect it and see what happens.

Fixed and better than new!!!
 

$750 fixed it. New Conductor Plate. Very slight signs of wear in the pan or on the magnet. I think of it as being preventative maintenance, would have liked to have done it later than 136,000 but OK now.

Did I say conductor plate? $750 is not a bad price if you farm out. DIYable.