2003 Ford Windstar Transmission

I have a 2003 Ford Windstar with 83000 miles. Today while driving home the transmission stopped applying power to the drive wheels. Without any warning the rpm's went up as though it had slipped into neutral. Now it won't go into any gear. Prior to this I have never had any trouble with transmission slippage, or hard shifting. A few months ago I did have some trouble with the car "bucking" mildly while underway, which cleared up in about a week. At the time I couldn't tell if it was the engine or the transmission which was missing a beat. I've been told it could be the vehichle speed sensor. The friend who told me that also said that could be why my abs trouble light sometimes comes on and stays on until I shut the car off and restart it. The road I live on is subject to flooding, and every couple of months I have to drive through several inches of water to get to work. Could this ruin a sensor?