ATF: MB spec 236.14. Although I have been told by multiple (reputable) tranny rebuilders that I can just use regular red ATF. What is important, whether I use the "official" spec or not, is to change the fluid (and filter) every 30-40,000 miles. This is what I am doing in my own two 722.6 vehicles, although I follow the spec on customer vehicles, just in case.

Typically, the front center speed sensor (one of the two on a little stick that wobbles front to back) cracks. I suppose, in theory, you could just replace that piece (if you can find it separately), but generally you might as well just replace the entire plate.

Regarding the other items: has any liquid gotten into the shifter unit (easy to spill into the opening, unfortunately) or has any ATF wicked its way up the harness into the TCM? Check for ATF in the adapter plug. Very common as the cause for weird behavior or codes.

Hope that helps!

Cheers,
-Bruce

__________________
1976 240D [W115.117/616.916] (acq 11Jun76)
1990 MB 300D 2.5 Turbo [W124.128/602.962] (acq 4Sep15)
1991 SL250D (ex-300SL-24) [R129.061/OM602.962/722.618, was M104.981] (acq 25May12, converted to diesel)
1993 Jeep Cherokee [XJ] (acq 12Apr14)
2013 GLK250 BlueTec 4MATIC [X204.904/651.912] (acq 24Jan26)