Magnum XL 6-Speed KIT TUKT12021/ 2.97 first .80/.63 OD



TUET12021 TREMEC T-56 Magnum XL 6-speed Transmission Kit
for the 2005-2018 Ford Mustangs

  • Gear Ratios 2.97, 2.10, 1.46, 1, .80, .63
  • 26 spline input, 31 spline output Shafts
  • Torque rated 700+ft/lbs
  • SFI 6.1 Certified bellhousing
  • Direct mounted shifter
  • Analog Electric Speedometer Sensor 


Modern Driveline was the first to install a Magnum XL into both V8 and V6 Mustangs and has the most in-depth knowledge and parts in the industry!

Don’t make the mistake of purchasing somewhere else only to be left with incomplete parts and advice.
All our products are backed with Lifetime technical support.
See us first for your MT-82 to Magnum XL upgrade. 

We extend the manufacturer’s warranty for an extra year and that is from the date of install.

TREMEC® T-56 MAGNUM XL 6-Speed S197/S555 Mustang Double Overdrive Transmission

TUKT12021 with a 2.97 first gear and .80/.63 Overdrives

Introduced to the marketplace in 2012, the Magnum XL is a continuation of the popular Magnum 6-speed series.
Featuring all the most important content from the original Magnum, the XL retains its brute strength and sophistication but eliminates its multiple shifter locations and dual speedo outputs

The Magnum XL is an extension of our revered Magnum 6-speed series.
Featuring all the most important content from the original, the XL retains the Magnum brute strength and sophistication but adds an extended-length tail section designed to eliminate the clumsy semi-remote shifter found in many popular late-model applications.
Currently available only for 2005-up S197 & S555 Mustangs, the Magnum XL includes an SFI-approved steel bell-housing with an enclosure plate, a swap-specific cross-member, and an OE-quality transmission mount. For strength purposes, the Magnum XL also requires a 26-spline clutch and one-piece driveshaft (sold separately).
Some applications may require speedometer e-calibration via ECU tuning or through the use of a separate signal converter.

For a complete Tremec T-56 Magnum XL install package, Contact us for an installation package that includes, Flywheel, clutches, module/harnessing, driveshaft, oil, and installation instructions.

Features & Benefits:

  • 85mm center distance.
  • 700 lb-ft effective torque capacity.
  • Direct shift aluminum shifter for smooth, positive shift action.
  • SFI 6.1 certified Scatterproof Bellhousing
  • Triple cone synchronizers on gears 1-4, double cone synchronizers on gears 5-6, as well as reverse.
  • Accurate, smooth, high-rpm shift capabilities.
  • 26 Spline input shaft
  • 31 Spline output shaft
  • Direct-Fit replacement crossmember
  • Electric analog sensor speedometer.


    T56  Magnum XL  cannot be ordered online, we ask that you please call us at: 

    One of our sales agents will be more than happy to process your order.

    This item can only be shipped via ( LTL ) – Light Truck Load service UPS ground is not an option
    due to the weight of the item, see below.

    UPS LTL freight shipping cost to a commercial or nearest freight depot address only
    within the lower 48 states.
    ( Shipment to a Residential Address is an additional $125 and can be billed after delivery )


Part Number
Application Torque Cap.
Gear Ratio Chart
1st 2nd 3rd 4th 5th 6th Rev
TUET16886 FORD 700 2.66 1.78  1.30 1.00 0.80 0.63 2.90
TUET11940 FORD 700 2.97 2.10 1.46 1.00 0.80 0.63 2.90
TUET12021 FORD 700 2.97 2.10 1.46 1.00 0.80 0.63 2.90
TUET16901 FORD 700 2.66 1.78 1.30 1.00 0.80 0.63 2.90

HOW TO: T56 Magnum XL 6-Speed Swap a 2011-current Mustang GT

HOW TO: Motorz TV Feature Upgrade 2008 Mustang GT to a T-56 Magnum XL Trans.

2011-current V6 Mustang T56 Magnum XL 6-speed Swap

05-2010 Mustang Conversions

Additional information

Weight 3760 oz
Dimensions 46.5 × 22 × 20 in


Hover over image to enlarge



  1. Extended-length (XL) extension housing
  2. Shifter location that mimics several late-model applications
  3. Reverse inhibitor solenoid
  4. Electronic speedometer output
  5. Fluid drain ports
  6. Common T56 style bolt pattern
  7. Mounting pad for OEM style hydraulic slave or aftermarket guide tube
  8. Clutch fork exit window
  9. Unique isolator style shifter for reduced noise, vibration & harshness (NVH)
  10. Reverse light switch
  11. Slip yoke output
  12. Trans mount location







6.6″ 21.7″ 38.4″ 13.0″ 12.25″ 2.75″



Driving Techniques
A 500-mile break-in period will prevent premature wear and possible damage to the transmission. During the
break-in period, you must avoid high RPM shifts and “drag” starts. The clutch must be fully disengaged to shift
the transmission. Do not use excessive force when shifting the transmission. If you experience clash shifts
(grinding), check clutch travel to ensure proper air gap is achieved. Another possible cause of clash shifting is
improper transmission installation (excessive driveline angle / resulting in poor driveline alignment). Do not hold
the transmission in gear by applying force on the shifter. This will damage the pads on the shift forks and may
result in significant damage to the transmission.


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