Ford 2003 Mustang Workshop Manual page 2731

6. Install the second speed gear bearing spacer and the second speed bearing.
7. NOTE: Align the slots in the second gear with the tabs on the synchronizer blocking ring.
Install the second gear onto the output shaft.
8. Install the thrust washer and the snap ring.
9. NOTE: If not done so previously, soak the blocking ring in MERCON® Multi-Purpose ATF
Transmission Fluid XT-2-QDX or equivalent for ten minutes.