Ford 2003 Mustang Workshop Manual page 472

36. WARNING: The differential clutch spring (4214) is under tension. Remove the spring
carefully. Failure to follow these instructions may result in personal injury.
Remove the differential clutch spring.
37. Remove the differential gears.
1. Remove the two differential pinion gears (4215) and pinion thrust washers (4230).
2. Remove the two differential side gears (4236) with the clutch packs (4947) and the shims
and tag them "left" and "right."
38. CAUTION: Keep the differential clutch packs in order. Do not mix them. Always
reassemble them in the same sequence.
Remove the differential clutch packs and shims from the differential side gears.
Clean and inspect the remaining differential components for wear and damage. Install
new parts as necessary.