T-45/TR3650 to TKX 5-Speed Conversion Package | 1999-2004 Mustang GT 4.6L

T-45/TR3650 to TKX 5-Speed Conversion Package | 1999-2004 Mustang GT 4.6L

T-45/TR3650 to TKX 5-Speed Conversion Package | 1999-2004 Mustang GT 4.6L

Description

Key Features

  • 600 lb-ft torque capacity with 8,000 RPM engine speed rating and safe shifts at 7,500 RPM
  • 26-spline input shaft eliminates the 10-spline weak point of factory T-45 and TR3650 transmissions
  • 31-spline output shaft matches factory driveshaft spline count for simplified installation
  • Compact end-loaded case design fits transmission tunnel without floor modifications
  • Multi-cone synchronizers with sintered bronze and carbon hybrid rings for smooth high-RPM shifts
  • Three-piece ribbed aluminum housing provides structural stiffness and reduced NVH
  • Gaskets at all flanges eliminate fluid leaks
  • ASTM 4615 special-grade steel gears with oversized widths for maximum durability
  • High-performance billet aluminum short-throw shifter isolates road noise
  • Complete customizable package—transmission, bellhousing, clutch, crossmember, and all supporting components
  • 100% brand-new OEM-quality TREMEC components

Description

The factory T-45 and TR3650 transmissions in 1999-2004 Mustang GTs share a critical weakness: a 10-spline input shaft that becomes the failure point once you push past 400 horsepower. This complete TREMEC TKX conversion package eliminates that bottleneck entirely, replacing the factory 5-speed with a purpose-built aftermarket transmission rated for 600 lb-ft of torque and safe shifts at 7,500 RPM.

The TKX represents TREMEC's ground-up aftermarket design—not an adapted OEM transmission. Multi-cone synchronizers with hybrid sintered bronze and carbon rings deliver smooth, precise shifts even at high RPM, a dramatic improvement over the notchy engagement common in worn factory units. The internal three-rail shift system with steel shift forks and ball detents provides crisp, positive gear selection through the included high-performance billet aluminum short-throw shifter.

Durability comes from ASTM 4615 special-grade steel gears and shafts with oversized widths for increased torque capacity. The three-piece ribbed aluminum housing—main case, intermediate plate, and rear extension—provides exceptional structural stiffness while minimizing noise, vibration, and harshness. Caged needle bearings in all gear positions and gaskets at every flange ensure long service life and leak-free operation.

The compact end-loaded case design fits within the factory transmission tunnel without floor modifications, and the 31-spline output shaft matches the factory T-45/TR3650 output spline count for simplified driveshaft compatibility. MDL's guided package selection walks you through choosing the right gear ratios, clutch system, and supporting components for your specific application and power level. Multiple TKX gear ratio configurations are available to match your rear axle ratio and driving style.

What's Included

  • TREMEC TKX 5-speed transmission (choice of gear ratio configurations)
  • Ford Modular bellhousing (aluminum or steel construction)
  • TKX-to-Ford Modular hardware kit
  • ARP flywheel bolts
  • Complete clutch set (multiple disc diameter and torque capacity options available)
  • Pilot bushing (for twin-disc clutch applications where applicable)
  • ARP pressure plate bolts
  • Custom crossmember for 1999-2004 Mustang
  • Speedometer drive gear (16-21 tooth options for ratio calibration)
  • Speedometer gear retaining clip
  • Electronic speedometer sensor
  • Transmission fluid (3 quarts high-performance MTF or ATF)
  • Reverse light wiring harness
  • Output yoke (1310, 1330, or 1350 U-joint size options)
  • MDL lifetime technical support
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