MM News

New! Swapping an IRS into your Fox Mustang? MM makes it easier with a brake line kit made just for this conversion. Bolts-in, with no cutting or flaring of brake lines. Designed to fit standard IRS brake hoses.

New! MM now offers a tool for the giant nut securing a Mustang Hydroboost. This MM socket fits the 1-7/8" nut holding the Hydroboost to the firewall mount. Required when changing a Hydroboost unit.

New! MM's billet aluminum Pedal Box Spacer for Fox Mustangs. Replace the breakage-prone OEM plastic spacer when converting to manual brakes or Hydroboost.

Canadians! Please read the latest about ordering from Canada/shipping to Canada.

We've posted the parts list and link to the video of MM's Mustang in /DRIVE Tuner car Shootout

Turnology drives their S550 after they installed the latest MM Starter Box. Read about the Starter Box and their test drive report.

New! MM Starter Box for S550 Mustangs. Includes Koni dampers, MM Caster Camber Plates, choice of Eibach or H&R springs, and Eibach swaybars.

Torsen T2R torque-bias differential, High Bias, Ford 8.8” differential
Actual product may differ from photo.
  • Torsen T2R torque-bias differential, High Bias, Ford 8.8” differential

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  • Item # TOR-F88ZTxxHBI
  • Manufacturer: Torsen

Select Option(s):

Must Select Axle Type



High bias Torsen T2R torque-biasing differential is a full-time torque-biasing system, not just a limited slip differential. The Torsen differential has a unique helical-gear design with no clutch plates or preload springs. It provides continuous, uninterrupted torque output, torque biasing, and differentiation in one integral unit. The Torsen greatly improves traction because it is continuously and instantly responding to torque feedback from the tires, sending more torque to the tire with the most traction.

The 4:1 TBR of the Torsen T2R means that this differential is capable of delivering up to four times as much torque to the tire with better traction than is delivered to the tire with the least available traction. Excellent for the tight turns typical of autocrossing.

By comparison, the standard Torsen T-2 can deliver about 2.5 times as much torque to both rear tires, collectively, as an open differential can, given the same conditions.

Torsen differentials have NO clutches or preload springs.

Ford equipped several Mustangs with a Torsen differential as original equipment:

  • FR500S, Boss 302R, Boss 302S
  • Boss 302 (optional)
  • Boss 302 Laguna Seca
  • 2013-14 Mustang with the OEM Track Pack option
  • Torsen differentials provide a very high resistance to wheel spin during hard acceleration, yet still allow easy turn-in at corner entry.
  • Inside rear tire spin at corner exit is held in check because the Torsen distributes more torque to where it can best be used; the outside tire.
  • High TBR of 4:1 is ideal for autocrossing, yet not a hindrance for street use or open-tracking.
  • The Torsen’s unique torque distribution ability creates an understeer-canceling yaw effect that helps the car drive through the corner, increasing the lateral acceleration potential.
  • Cornering traction is maximized by reducing the understeer typically caused by preloaded clutch-type differentials.
  • Torsen differentials have no clutches to wear out.
  • High torque bias ratio of 4:1
  • Helical-gear torque-sensing design
  • No clutches or preload springs.
  • No unusual gear oil requirements
  • Friction modifier is NOT required.
  • Available in either 28-spline or 31-spline
  • NOT included: Ring gear, bearings, seals, oil, etc.

When ordering you must select either 28-spline or 31-spline, as appropriate for the axles in your Mustang.

Original Axle Splines for 8.8" Differentials
Vehicle Axle Spline
1986-2004 Mustang with 8.8" solid axle 28
1999-2000 Mustang Cobra IRS 28
2000 Cobra R IRS 31
2001-2004 Mustang Cobra IRS 31
1987-1988 Thunderbird Turbo Coupe 28
1989-1997 Thunderbird IRS 28
1989-1996 Cougar IRS 28
1993-1998 Lincoln Mark VIII IRS 28
2005-2014 Mustang V8 31
2011-2014 Mustang V6 31
  • Torsen differentials are NOT recommended for high-powered drag race launches on sticky tires.

See this document for guidelines on installing a Torsen Differential in the Ford 8.8" axle housing.