Transmission Problem after Raining (Flooded)

Hi
I am new to this form and know very little about the cars. I have 1998 Grand Am - 6 cyl - 3.1 L with Automatic Transmission. Yesterday after a heavy rain, my car stopped in almost 1 ft water. After 4 hours with boosting, I could start but water was mixed with engine oil. So I did change oil right away. But I was having a problem with shifting grears. 3rd, 4th,, or may be, all. RPM guage goes upto 5 to change the gear to next level. Please help or suggest something. I'd really appreciate your help. According to dealers, I have to change almost everything. Please give me your opinion.

1 foot? thats deep. was it coming in the doors? you may need alot done. your carpets and stuff will get nasty and start to smell a little if they arent dried out properly. you transmission very well could have water in it, if so you may need a new one or the one u have taken apart and dried. If all the electronics got wet they needed dried before juicing them up. but 1fts not that deep, unless u were doing 30mph. Maybe theres an easy way out of this, I've never drove through that much water but I have washed the engine down with a powerwasher and soaked everthing and it hasnt gave me any fits. \,,/

1 foot? thats deep. was it coming in the doors? you may need alot done. your carpets and stuff will get nasty and start to smell a little if they arent dried out properly. you transmission very well could have water in it, if so you may need a new one or the one u have taken apart and dried. If all the electronics got wet they needed dried before juicing them up. but 1fts not that deep, unless u were doing 30mph. Maybe theres an easy way out of this, I've never drove through that much water but I have washed the engine down with a powerwasher and soaked everthing and it hasnt gave me any fits. \,,/
Thanks for replying. Major problem is Transmission, other things could be done easily. Some one suggested me to check VSS (Vehicle Speed Sensor), it could have gone bad and finally shorted to the point where the ECM thinks the car is moving and will not allow the trans to downshift. Now I really dont know, what are these things, but if this is the reason, I could go to Mechanic and ask him to check. What do you suggest?

Theres three things I dont do. Windows, dishes and transmissons. LOL! Sorrie I had to say it. But I would ask around here and else where about the VSS. You probley did short some stuff out from the short swim though.

I work on cars, trucks, tractors/ farm equipment etc. but when I need tranny work I call someone or take it to a shop to get the work done. I accually have a friend, whos on vaction now, who I trade work for, he fixes my tranys and I fix stuff for him. Works out great, as long as he needs work done. LOL! Hope this gets you headed in the right direction. keep checking back here, someone else surly has taken their car for a swim.

Hi guys,, finally I got it. It was TPS (Throttle pressure Sensor). Now its running nice and smooth as before. Thanks for all your help. Have a great day.