if it's a 200-4r, just unplug the connector, takes about 30sec and no tools. hell you can do it with all 4 wheels on the car (well, if you're thin!) if that works, it's an easy job to replace the valve/solenoid.
basics--drop the pan. follow the wire(s) to the valve. IIRC theres a cir-clip in there, pull that and pull the valve BE CAREFUL!!! fluid will come out--FAST! adn there are one or two small parts that you need to have in the right order. sorry i can't remember more, but a good repair manual will be very helpful! installation is reverse of removal.
bowtie overdrive sells an upgraded solenoid and may have a write up on how to do it right.