Ford 2003 Mustang Workshop Manual page 2896

Remove the interlock plate.
Using a 5/32-inch drift and a hammer, remove and discard the roll pins. Slide the gear
select solenoid lever and the selector pin from the shift rail.
2. Disassemble the fifth/sixth and reverse shift rail as follows:
Using a 5/32-inch drift and a hammer, remove and discard the roll pins. Slide the collar
and the reverse shift lever from the shift rail.
Slide off the fifth/sixth shift lever and shift link.
3. Inspect the shift rail components.
Check the rails, shift forks, shift levers and shift links for wear or damage. Install new
components as necessary.
Check the shift fork pads for wear. Install new pads as necessary.
4. To assemble, reverse the disassembly procedure.
Install new roll pins.