I'd check the forum PowerStrokeNation as they have the years for everything covered. Use the search function and hopefully you'll find if there's an easy fix for yours. While I have the 7.3L, mines older and going to be a different tranny. Check the fluids, and take a look at the sensor as others have said. I spoke the Mr. Transmission last year having them do an inspection on mine to make sure it was good for the season to tow and they seemed extremely knowledgeable in the Ford transmissions for the 7.3. I don't remember their price for replacement but they knew a lot when I was spoke to them and I had a very good feeling about a future replacement through them.

http://www.powerstrokenation.com/for...ssion-related/