School me on the 4hp22

[Mike W.]

Figured I'd bump this thread rather than start anew. Now that the weather's getting warmer, the transmission is a bit recalcitrant. Sometimes kickdown works exactly as expected, other times I can have the pedal floored and it still upshifts at 2k rpm or doesn't downshift. I can't find rhyme or reason for why it sometimes works and sometimes doesn't. The kickdown cable is adjusted properly, and when kickdown works, it works perfectly. When it doesn't, it just flat doesn't.

Is there anything in particular that could cause this sort of behavior?

Dirty or gummy fluid causing a valve to stick? I can't remember, have you changed the fluid yet? On an E21 I used to have, 3HP22, but they are very, very similar except for the OD 4th, when cold it would go from 1st to 3rd for the first half mile or so. Several changes of what was in the pan and it was just fine until the car got hit and totaled.

[Jeremy]

I did a simple drain and refill with the last oil change. I didn't drop the pan to check the filter though. Maybe I'll do that on the next oil change.

[Jeremy]

Just to bump this. I did do a couple of simple fluid changes (drain and refill) with the same results. I finally got around to changing the filter, which wasn't nearly as bad a job as I feared it would be, and everything seems to be better now. Some unpleasant looking stuff came back draining out of the filter when I released it. Dark grey in color. I hope that's not a bad sign.