Drop the tranny pan, pull the #2 solenoid, its the gold, brass looking one. Soak it in PB Blaster for a couple of hours. Though before you immerse it, test it with a 12v power source, so you get a baseline of how it sounds when you hit it. Then submerge it in PB Blaster, and leave it. But before you do all that, head to your local toyota dealer and pick up a few quarts of T-IV tranny fluid, and then hit autozone and get a filter kit, comes with a nice rubber gasket to install. Recommend you put the the car on ramps in the front, and jackstands in the rear. I did this and had plenty of room to do the work.
Or you can take it to a reputable mechanic and let them get messy for you.