Synchronizer Ring

Check the clutch gear teeth for damage and broken.
Check internal surface for damage, wear and broken threads.

Fig 1: Checking Clutch Gear Teeth
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Force the synchronizer ring toward the clutch gear and check clearance "A." If "A" is less than the limit, replace the synchronizer ring.
Minimum limit: 0.5 mm (0.020 inch)

Fig 2: Checking Clearance To Synchronizer Ring
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.