Ford 2003 Mustang Workshop Manual page 399

16. Using the special tool, install the new differential bearings.
17. Position the differential assembly, including the differential bearing cups and differential bearing
shims, in the differential housing. Install the bearing caps and bolts.
18. Position the special tool.
1. Rotate the differential case to verify that the differential bearings have seated correctly.
2. Position the special tool.
19. Measure the differential case runout.