Check TSBs
WARNING: This page is about a different car, the 2002 Ford RV Cutaway, 2002 Ford Econoline, 2002 Ford E550 Super Duty, 2002 Ford E450 Super Duty, and 2002 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Refer to all Technical Service Bulletins that pertain to the transmission concerns, and follow the procedure outlined.