There are just three versions of the T-45.
They are tagged as follows:
1381-001 1996-1998 Mustang 5.0 GT - 8-tooth internal speedo gear & VSS
1381-002 1996-1998 Mustang 5.0 COBRA - 7-tooth internal speedo gear & VSS
1381-011 1999-2001 Mustang 5.0 GT & COBRA - digital Electronic OSS Speedo
Those with the VSS sending unit will drive a FOX Mustang cable speedometer if the white plastic plug is removed from the VSS.
When choosing a T-45, the 1999-2001 units seem to be more reliable.
- Carbon-fiber synchros for gears 3, 4, 5, & Reverse
- A solid tube for the throwout bearing sleeve that won't snap off
- The Factory Service Bulletin for the 5-R Forks is already installed
- The 3-4 forks in these units seldom shatter like the 96-98 models
Remember that the 96-98 COBRA T-45 has the cross member located further back than the other Mustang transmissions.
When rebuilding a T-45 specify the 1-2 rings from a 2003/2004 COBRA T-56 so that all of your rings will be Carbon-Fiber.