Ford 2003 Mustang Workshop Manual page 427

14. Mount the differential case and the special tool in a vise. Using the special tool, check the
torque necessary to rotate one differential side gear.
If reusing the original clutch plates, the initial minimum break-away torque must be no
less than the specification. The minimum rotating torque necessary to keep the
differential side gear turning with new clutch plates may vary.
15. Using the special tool, install the differential bearings, if removed.
16. Position the differential ring gear and the differential case. Align the bolt holes by starting two
bolts through the holes in the differential case and the differential ring gear. Press the
differential ring gear on the differential case.