I have worked on a few of those transmissions in my time and can say without a doubt it may not fix it.Common causes for you symptom you describe can include control valve body,turbine shaft seals,channel plate or bushing spun in the channel plate,malfunctioning torque convertor blow off valve,faulty pcm,tcc solenoid,damaged tcc filter or a bad convertor.This off the top of my head and I may have missed a couple.Oh yes brake switch adjustment and incorrect modulator pressure.At your mileage it most likely is a combination of the above.Your best course of action would be an overhaul or live with the problem.Check the brake light switch adjustment and fix the entire trans or save your money.I don't feel a torque convertor will correct the problem,I would in fact bet more than the $5 you said you will pay for an estimate.