poolshark2014

I have a 96 V4 Grand Am that I am having Transmission problems with. This all started when I went to the bakery which was flooded because it rained like crazy.I was going up the ramp in deep water and my car turned off.I tried starting it back up but nothing until eventually it started and I gave it some gas to quickly get up the ramp before it would turn off again.I took off from the bakery to go to work and everyting was fine.The next day I noticed that the car was making a loud almost suctioning type of sound but didn't think much of it until today when I was going to town I noticed that the car didn't want to go any faster than 20mph and did not want to shift into second gear.Well I went ahead and changed the transmission fluid and filter but still no luck.The car has about 160K miles on it and I have kept up with all maintenance on it.Some people tell me that it might be the modulator located close to the transmission but I can't find it.I don't know what might be the problem. Any Ideas?