FYI --
Late-model Mustang performance has been a staple of the automotive aftermarket since the late-'80s, when the real potential of the 5.0- liter Fox models was realized.
It continues today, after a few more generations of the original pony car and its major components. When the 5.0-liter was retired in favor of the "modular" 4.6-liter overhead-cam V-8, a new manual gearbox was also employed to take over for the previously used Borg-Warner T-5. The new box, also from B-W and designated T-45, was intended to be more durable to handle the increases in power and weight, but the new 'box also brought new troublesome characteristics, including hard- shifting, excessive gear noise, and a chronic tendency to pop out of reverse.
Keisler Engineering has addressed the problems with the T-45 gearbox in 1996-2004 Mustangs, and is now offering remanufactured units in two forms: street and street/race. The street model uses upgraded carbon- fiber synchronizers along with new bearings and seals; gears are replaced as needed. Also included is a new, billet machined PRO shifter. The street and race model also includes a new SFI approved safety bellhousing, high-strength alloy bearing retainer, and a new, super-duty oversize input shaft measuring 1-1/8-inch with 26-splines (which requires a non-stock clutch disc).
Both transmissions can be ordered with the optional adjustable shift- travel stop version of the PRO shifter to guard against internal gearbox damage during competition-style shifting. To find out more about the remanufactured T-45 gearboxes or to check out Keisler's line of five- and six-speed transmission conversion kits, go to
Patrick