My 200-4R has developed a little problem. Works great when its cold, converter locks and unlocks like it should. It has the 4th gear lockup switch. After it warms up it doesn't want to unlock. It doesn't kill the engine when I stop as it unlocks when it shifts into 1st. If I don't use the 4th gear position there is no problem. But once I use the 4th gear it acts up and locks up in all but 1st gear. I ordered a new solenoid hopefully that will fix it. The solenoid comes with a new 4th gear lockup switch. This tranny worked perfect for over a year.o No: Bob H.
There is something stuck in the sol. The new one should take care of the problem BUT something got into it to make it stick. Carefully look in the pan when you drop it to see if there is any indications of something going wrong! Also make sure there is a magnet in the pan. Good luck Mike
Also, run auxiliarty in-line transmission filter, and high capacity cooler. Flush valve body and case area where lockup servo installs. It doesn't take much to make the solenoid stick just like you describe.