2001 Ford Taurus transmission does no go in gear

I was driving on the freeway and the car just stopped going forward. I pulled over and dried to put it in gear reverse and forward, but nothing happened. I had AAA tow it to my house. Later in the day I started the car and tried to see if it would go in gear but nothing happened. I bought the car a month a go and have driven it 400 miles without any problems but there was some noise when I drove but it felt like tires. WHen at home I checked the fluid and noticed it was over filled. Additionally, since at home the engine light comes on now when I start the car, but it did not when the car stopped initially going forward on the freeway. My initial reaction is to drain some fluid, but I am not sure why it was running so well before with too much fluid. The engine light baffles me though. I know there is a sensor to the transmission but I am not sure if that could be the problem. It feel like the RPMS shange a little when I put it in to gear but no movement. Please help and I am donating money. Thanks Mike Frank