1985 Toyota Camry Transmission doesnt work in forward gears

The Camry sat for a 2-3 months, prior to this the engine and transmission worked perfectly. The trunk has a leak and during the rains the car got a lot of water in it, the electrical controlling the seat belts etc is shot, all faults are now isolated. When I went back and boosted it the transmission doesnt engage in forward gears. Also the instrument cluster does not have power, I cannot figure out which fuse it is. I drained the tranny fluid and installed a new filter. There are no leaks. Is this an electrical problem? What else might it be? My car repair magazines tell me to take it to the shop, I cannot afford that, I have no info on how the dang thing works. Thanks