Ford 2003 Mustang Workshop Manual page 2878

9. Remove the third gear needle bearing.
Inspect the needle bearing for wear or damage. Install a new needle bearing as
necessary.
10. NOTE: Install the special tool with the flat side facing the bearing.
Using the special tool, press the output shaft front bearing from the output shaft.
11. Inspect the synchronizers.
Check for worn, nicked or broken teeth. Install a new synchronizer as necessary.
Check keys for wear or distortion. Install a new synchronizer as necessary.
Check springs for distortion. Install a new synchronizer as necessary.
12. Inspect the synchronizer blocking rings.
Check for wear or damage. Install new synchronizer blocking rings as necessary.
Check the clearance between the synchronizer blocking ring and the gear.
Position the blocking ring onto the gear. Make sure the correct blocking ring is
measured with the correct gear and that the blocking ring is fully seated on the
gear.
Insert a feeler gauge and measure the clearance, while applying pressure and
rotating the blocking ring. The measurement should be the same around the entire
circumference. If the clearance is less than 0.38 mm (0.015 in), install new
blocking rings.