Just dropped the pan to change the filter. Nothing wrong with tranny operation 105,000mi thought it was due. Changed out the filter with Motorcraft filter, cleaned pan and reinstalled. About 4 quarts came out so I put 4 back in. Started the truck shifted it through all gears and the truck won't move forward or reverse.

 

Check and make sure the o-ring on the old filter didn't stay in the transmission. If it did the new filter might not be seated properly and pulling the fluid. Not much help, but other actual trans people will chime in I'm sure.

 

The filter inlet could be too short, and four quarts is not enough. It's really low.