Ford 2003 Mustang Workshop Manual page 2918

26. Clean the mating surfaces of the transmission main case and the shift detent cover. Apply a
bead of silicone rubber to the sealing surface on the transmission case. Install the cover and
tighten the bolts.
27. Rotate the transmission to a horizontal position. Install the countershaft extension assembly and
the fifth/sixth gear shift fork. Make sure the splines are fully engaged.
28. NOTE: Remove the countershaft extension shim from the extension housing.
Install the extension housing and tighten the bolts.
29. NOTE: Rotate the transmission to the vertical position.
Using the special tools, measure the countershaft extension end play by pushing upward on the
countershaft extension. Record the measurement.
Insert a suitable bar into the adapter plate plug hole until it engages the countershaft
extension.