I picked up an 89 300E back a few months ago, and I posted here about an issue where, while driving around, usually around 40mph, the tranny would suddenly kick down 1-2gears, and hold there like i was driving up the side of the mountain. The only way to get it to shift back up again is to either gun it for a few seconds, or put the gate in neutral. when i let up or put it back into drive, it seems to act normal for a random amount of time, then starts acting up again. I took the advice of some people here and disconnected the kickdown switch under the pedal. It had no effect whatsoever, in fact, I think it got worse. Anyone have any advice on the matter? I didn't pay much for the car, and aside from the numerous electrical gremlins, the car starts right up and drives smoothly, with the engine revving easily. I really am trying to keep a 'do-it-yourself' approach to this car, as i want to keep the costs down as much as possible. I have not flushed the fluids/replaced the filters, as a)it shifts quite smoothly while it's functioning, and b) the car has over 100k, and I'm afraid it may stir up any shavings in the pan, plus c) this car doesnt even leak from melting snow, it's that tight.
Any help would be most appreciated!
other issues that i will address later;
radio's broke/dead (i don't care really, but it might be important to note)
numerous switches/electrical accessories don't work/broke aka power antenna, power seat(s), defrosters, heated wiper basin (you get the idea)
Change all the fluid in the transmission including the torque converter. Change the filter. Do not be "afraid" of disturbing any "shaving". I'd be afraid of having any in there at all. You also need to check all your vacuum lines to ensure there are no loose or cracked rubber connections etc.
Properly maintained, these transmissions will last a long, long time. Not maintained and you'll spend as much replacing it as you did to probably purchase the car. To DIY all this is a fairly simple process. I would assume you are "handy" around cars and have a decent assortment of tools, a good jack and stands. Use the search function of this site and you'll find plenty on this subject.
actually, the first thing i did was search for similar issues with the tranny on this forum. to be frank, either i wasn't typing in the correct search keywords, or they pointed to the B3 piston (doesnt match exactly, it shifts fine other than the kickdown), replace/rebuild the tranny (while this fixed the problem, nobody seems to have identified exactly what's going on) or, in the case of fluid replacement/filter, it's been directed that way due to another symptom; violent shifts, which, while making sense, im not sure indentifies my issue. I'll look into dropping the pan, replacing the gasket/flushing the systems and at least getting it a once-over for vacum leaks, etc.
89 300E Erratic tranny Kickdown? 
Linear Mode
