93 Escort auto-tranny not up-shifting

[Wildwrench]

Hi Everyone,
My 93 Escort LX (1.9 engine) automatic tranmission seems to have a problem. Started several months ago with late up-shifts into Drive and later the same into OD. Last week, I had the fluid and filter replaced (really dirty). It was NOT flushed. Now, there are times, usually when the engine is cold, when the up-shift out of Low doesn't happen. Sometimes it appears stuck in neutral. I play around with the shifter, dropping it out of OD into D, then sometimes into Low (at slow speeds, of course). After several attempts, the shifting works okay again. Often, there are no more problems that day. Oh, the odometer is just over 118,000. No other problems with the car (I'm knocking on wood).
Could the fluild/filter change have caused the up-shifting problem? What is the most likely mechanical/electrical cause?
I want to get this corrected before it gets worse and leaves me stranded.
Thanks for any and all replies.

[mightymoose_22]

If you can afford to do so, I would suggest taking the car in to have the transmission flushed... and I would watch when they do it. I just don't trust those guys sometimes when they get that machine out!
WHen you changed the fluid before (and it was dirty) you left behind lots of dirt fluid in the cooler and other parts of the transmission. Once you have completely eliminated fluid as a cause, then move on to the more complex stuff.

You said the fluid was very dirty when changed... was this the first time in 14 years? If the tranny hasn't been cared for, it could very well be damaged. Hopefully cleaning it up will do the trick.