Ford 2003 Mustang Workshop Manual page 2534

NOTE: Inspect the output shaft bearing surfaces for scores. Inspect the output shaft splines for wear.
Inspect all bushings.
9. CAUTION: Make sure the seals are lapped correctly. Internal damage may occur.
Install the two direct clutch seal rings.
10. Install the output shaft hub.
Position the output shaft hub.
Install the retaining ring.
11. Install the three output shaft seal rings.