1979-2004 Ford Mustang TKO Swap Guide

Posted 7/5/2016 by Phillip Perez

With adding power to any car, it is a hassle to put the power to the wheels through the stock transmission. The stock transmission in your Fox Body or SN95 Mustang can only hold so much power. That is why many Stang owners turn to the Mustang TKO swap. Thanks to Ford Performance’s TKO transmissions, completing a TKO swap on your Mustang is simple. This is a very basic swap that can take you a weekend to do along with some buddies to help out!

Mustang TKO Swap Parts

Street Car Bellhousing

79-95 5.0L or 5.8L Engines: We recommend the Ford Performance Bellhousing - M-6392-R58
  • Fits 79-93 with a 5.0L or 5.8L Windsor based motor and retains the factory clutch fork and pivot stud.
  • Can be used on 94-95 Mustangs but may experience exhaust to clutch fork clearance issues. Clutch fork is positioned at 9 o'clock position unlike 7 o'clock position of 94-95 Mustang. Requires a 79-93 Clutch fork, but can reuse factory pivot stud.
79-04 Mustang with 4.6L, 5.4L, or 5.0L Coyote Engines: We recommend the Ford Performance Bellhousing - M-6392-M46
  • This is the bell-housing to use if bolting a Tremec to your 1996-2004 4.6L or 5.4L equipped Mustang and retains the factory clutch fork and pivot stud.
  • Also the bellhousing you need if you have a Fox Body with a mod Motor or Coyote Swap. You’ll need a 94-04 Clutch fork and pivot stud.

Street/Strip or Track Car Bellhousing

79-95 5.0L or 5.8L Engines: We recommend the Quick Time Bellhousing – RM-6065
  • Fits 79-95 with a 5.0L or 5.8L Windsor based motor and retains the factory clutch fork and pivot stud.
  • Can be used on 94-95 Mustangs but may experience exhaust to clutch fork clearance issues. Clutch fork is positioned at 9 o'clock position unlike 7 o'clock position of 94-95 Mustang. Requires a 79-93 Clutch fork, but can reuse factory pivot stud.
79-04 Mustang with 4.6L, 5.4L, or 5.0L Coyote Engines: We recommend the Quick Time Bellhousing – RM-6081
  • This is the bell-housing to use if bolting a Tremec to your 1996-2004 4.6L or 5.4L equipped Mustang and retains the factory clutch fork and pivot stud.
  • Also the bellhousing you need if you have a Fox Body with a mod Motor or Coyote Swap. You’ll need a 94-04 Clutch fork and pivot stud.

Crossmember

You will need a TKO specific crossmember for your applicable year model:
  • 79-81 Mustang has narrower frame mounting points and requires a custom fabricated crossmember as there are currently no pre-made units available.
  • 82-93 Mustang we recommend the heavy duty Stifflers Chassis adjustable crossmember, TCB-M09. You will also need the TCB-TKO spacer kit to obtain proper driveline angle.
  • 94-98 Mustang GT and 94-95 Cobra, Stifflers Chassis adjustable crossmember, TCB-M03. You will also need the TCB-TKO spacer kit to obtain proper driveline angle.
  • 96-98 Cobra does not require a crossmember as the bolt in mounts can simply be relocated on the frame rail to allow the use of the stock crossmember. If you desire a different crossmember, you can use TCB-M03, but the frame mounts will still need to be moved. You will also need the TCB-TKO spacer kit to obtain proper driveline angle if using the Stifflers piece.
  • 99-04 Mustang, we recommend the heavy duty Stifflers Chassis adjustable crossmember, TCB-M20.

Clutch

There are a myriad of clutch choices available to accommodate whatever combination you may have. For TR3550 and TKO500 applications, you will need a 10-spline clutch disc. For the TKO (3550 series) and the TKO600, you will need a 26-spline clutch disc. You can select the best clutch for your needs below:

Driveshaft

The TR3550 transmission uses a 28-spline output shaft. TKO (3550 series), TKO500 and TKO600 Tremec transmissions use a 31-spline output shaft. Here is what you’ll need to connect the transmission to the rear end:
  • 79-93 Mustang using a TR3550 can re-use your existing manual transmission driveshaft or use Ford Performance Aluminum Driveshaft M-4602-G. If using a TKO (3550 series), TKO500 or TKO600 can re-use your existing manual transmission driveshaft by swapping out the yoke with M-4841-A or use Ford Performance Aluminum Driveshaft M-4602-J.
  • 94-95 Mustang can follow the same driveshaft information for the 79-93, but you will also need the Steeda driveshaft spacer 555-7705.
  • 96-04 GT, 96-98 Cobra, and 03-04 Mach 1 using a TR3550 can re-use your existing manual transmission driveshaft by swapping out the yoke with M-4841-B or use Ford Performance Aluminum Driveshaft M-4602-G. If using a TKO (3550 series), TKO500 or TKO600 can re-use your existing manual transmission driveshaft or use Ford Performance Aluminum Driveshaft M-4602-J.
  • 99-04 Cobra will need a custom length driveshaft made for all Tremec applications.

Tremec TKO500/600 Transmission Information

The TKO-500 and TKO-600 five-speeds are Tremec aftermarket units that have been Mustang enthusiast favorites for many years. They are a great addition to help with extra horsepower and torque. All Ford TKO500/600 transmissions are 31 inches in overall length and weigh 105 pounds. They are equipped with an internal three-rail shift system and cast-iron shift forks along Heavy-duty tapered roller bearings on the input, counter and output shafts reduce noise and improve the TKO's transmission performance. The single-piece countershaft and gears manufactured from 4615-grade steel allow the TKO series units to perform well under high RPM and torque applications.

Tremec TKOs have dual speedometer hook-ups, suitable for both cable-operated and sensor-operated speedometer systems and a beefy 26-spline(TKO600) or 10-spline(TKO500) input shaft with a 31-spline output shaft ensure that the TKO-series transmissions can handle a wide range of torque and horsepower requirements.