Steve Baur
Former Editor, Modified Mustangs & Fords
January 1, 2007

Step By Step

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Mmfp_0701_01z Ford_mustang_fox_body Rear_dropped_transmission
When five speeds aren't enough, it's time to step up to the T56.
Mmfp_0701_02z Ford_mustang_fox_body Transmission_housing
Currently, the Tremec T56 is used in the Dodge Viper, the Chevy Corvette Z06, and Aston Martin's DB7 Vantage and V12 Vanquish. Our particular application requires PN 1386-000-012, which provides you with a mechanical speedometer, a 10-spline input shaft and 31-spline output shaft, along with gear ratios of 2.97 First, 2.07 Second, 1.43 Third, 1.0 Fourth, 0.80 Fifth, and 0.62 Sixth. You can buy the transmission separately, but we recommend calling D&D Performance as it sells the transmission and all of the necessary swap parts for $2,699.
Mmfp_0701_03z Ford_mustang_fox_body Remove_midpipe
To begin the installation, we removed the mid-pipe and driveshaft.

When The EFI Mustangs of the late '80s blasted onto the scene, they benefited from a trick, new injection system that helped develop an abundance of torque. These 302s made great power, and many were backed by the T5 manual transmission-a four-speed with Overdrive that allowed the Mustang to run a relatively short First gear (3.35:1) and a short aftermarket rear gear (like 4.10s) while maintaining a comfortable cruise rpm thanks to a heavily overdriven Fifth gear. In 1993, GM's F-body twins ditched the five-speed for the T56 gearbox, a box that is more capable of handling even more torque. The T56 also increased fuel mileage due to its double Overdrive Fifth and Sixth gears.

Once the Mustang switched to modular power in 1996, its inherent lack of torque allowed the manufacturer to make mild upgrades to the five-speed unit until 2003, when the super-charged Cobra Mustang's 390 lb-ft of torque required something far more capable.

Today, the latest S197 chassis Mustangs still employ the five-speed in Tremec 3650 guise, but many Mustang owners have sought out the T56 gearbox, both for its extra power-handling capacity and its six-gear configuration.

Years ago, we installed a T56 in Project Superfly, and more recently, we dropped one into an S197 GT ("Love Plus One," Aug. '06). We haven't installed one in a Fox-body Mustang until now.

MM&FF's illegitimate project car, ProCharged Pony, has been fortified with numerous upgrades over the last four years, including a D.S.S. Racing 331ci, ProCharger-blown powerplant that has generated 580 rwhp and some 550 lb-ft of torque. Putting that generous amount of power to the ground is handled in part by the DTS 8.8 rear axle assembly, which has been muscled up with 33-spline axles, 9-inch axle ends, and an Eaton differential.