Ford 2003 Mustang Workshop Manual page 2906

7. WARNING: Make sure protective eye wear is in place.
Clean the case with solvent and dry with compressed air. Clean and check the sealing surface
for nicks or scratches. Inspect the case for cracks.
If the case is cracked, install a new case. If the sealing surface has nicks or scratches,
use a soft stone or crocus cloth to remove.
8. NOTE: If a new countershaft bearing is being installed, install a new bearing cup. Always install
new bearings and cups in a set.
Using the special tools, install the countershaft bearing cup.
9. NOTE: If a new mainshaft bearing is being installed, install a new bearing cup. Always install
new bearings and cups in a set.
Using the special tools, install the mainshaft bearing cup.
10. To assemble, reverse the disassembly procedure.