Ford 2003 Mustang Workshop Manual page 481

26. Remove the special tool from the differential clutch pack and differential side gear assembly.
27. Install the shim(s) on the differential clutch pack and differential side gear assembly.
28. Install the differential side gear assemblies in the differential case.
29. Install the differential pinion gear and differential pinion thrust washer assemblies in the
differential case.
30. Using a soft-faced hammer, install the differential clutch spring.