whats wrong with my automatic gear transmisiion on 1994 Mitsubishi Galant

I shift the gear to overdrive, but it engaged only in third gear, even I shift it to low gear but it stick to third gear and no over drive,even if I shift to direct over drive it still in third gear even if the RPM reaches to #3, the speed is only 80 km/ph, and the engine is getting wild.

Asked by for the 1994 Mitsubishi Galant
My 91 Galant is doing the same thing and I know its the Trans. module located on side of the gear console that needs replacing.