Ford 2003 Mustang Workshop Manual page 2709

3. Attach the transmission to the special tool.
4. NOTE: Position a drain pan under the transmission.
Remove the case plug.
5. NOTE: Position the gearshift lever in NEUTRAL.
Remove the bolts and the gearshift lever.
6. CAUTION: Do not attempt to remove the gearshift offset lever with the extension
housing bolted in place. A lug, located on the bottom of the gearshift offset lever,
meshes with the detent plate preventing enough rearward movement of the gearshift
offset lever to allow removal.
Remove the split pin and the gearshift shaft bushing.