For sale is a used T-45 manual five speed transmission removed from a 1999 Mustang GT with a 4.6 L V-8 engine.  Tag reads: 1381-011.  Comes with transmission shifter assembly, clutch fork, driveshaft yoke, bell housing bolts, 5-speed engine computer (GTG2), transmission wiring harness, clutch fork dust cover and bellhousing dust/block plate.  These are many of the parts that you would use to do a automatic to manual five speed conversion!  The Mustang was wrecked.  The transmission snaps into all gears good and input shaft spins smoothly.  The fluid appeared to be in good condition too (which has been removed for shipping purposes.)  Because this transmission and accessories were removed from a non-running vehicle, there is no warranty and no returns accepted. Nothing has been tested!  We only ship within the continental United States!  If you have any questions, please email me. Thanks! 

Here is a little bit of information about the T-45 Mustang 5-speed manual transmission: 

The T-45 first appeared with the 1996 Mustang as a stronger 5-speed manual transmission to mate with the new Modular 4.6 V-8 engine.  It was used until around February of 2001 when mid-production 2001 Mustangs began receiving the TR3650.  

The T-45 was a BorgWarner design that was exclusive to the Mustang.  Tremec (Transmission Technologies Corporation - aka TTC) acquired BorgWarner's Light-Duty Transmission Division  around 1997.  While the T-45 remained virtually unchanged, T-45 units produced by TTC bear the Tremec name.

The T-45 a single-rail shifting mechanism that is somewhat similar to the T-5 and was carried forward to the T-56.  The T-45 was the first Mustang manual transmission to have a fully synchronized reverse gear. 

There were only three versions of the T-45 produced and they were tagged as follows:

1381-001 - 1996-1998 Mustang GT

1381-002 - 1996-1998 Mustang COBRA

1381-011 / TNET1386 / TSET1386 - 1999-2001 Mustang GT & COBRA

1999-2001

For 1999, Tremec invoked several changes that made the T-45 more reliable.  This included stronger shift forks for all gears, a sturdier throwout bearing sleeve on the front housing and carbon-fiber synchro rings for gears 3, 4, 5, and reverse.

One additional change for 1999 was the inclusion of an all-electronic "OSS" speedometer sending unit.  1994-1998 Mustangs used an electronic signal to drive the speedometer, but these signals were generated by a "VSS" speedometer sending unit that was driven by a pair of gears.  Calibration for a "VSS" speedometer system was accomplished by selecting the correct gears to drive the sending unit.  For 1999 the OSS unit had no gears and was calibrated by settings in the "Tune" of the Engine Computer.   

It also appears that the 2001 Mustangs with the last production T-45's were tagged TNET1386 and TSET1386 with no discernable differences from the 1381-011 units other than the tag.

The T-45 uses the same shifter base as the T-5 and enjoys a broad selection of after market shifter choices that can improve the indexing of third gear on a quick shift.

There is only one set of production gear ratios for the T-45. The ratios are all 3.37, 1.99, 1.33, 1.00, and 0.67.  The ratio for reverse gear is 3.22.

The stronger reverse forks were incorporated into the production T-45's beginning in 1999 as well as stronger forks for gears 1-4.   The 3-4 forks in the 96-98 T-45's were notorious for breaking.

One additional weaknesses in the shift forks that were addressed by Tremec with the 1999 models is that the linkage, or selector "lugs" were made stronger to prevent the shift lugs from fatiguing and snapping off.  

The current official Fluid for a T-45 is Ford's Mercon-V which is a quality synthetic blend. 

 T-45 to TR3650 INTERCHANGE INFORMATION is as follows, The TR3650 uses a different Shifter base than the T-45.  A 1996-1998 T-45 can be replaced with either a 1999-2001 T-45 or a 2001-2004 TR3650 by using an electronic device called the "Dallas Mustang Speed-Cal" to convert the speedometer signal.