February 1, 2007
Tons of horsepower is good. Tons of horsepower with a drivetrain that won't break is even better. The Tremec TKO 600 will stand up to some serious power and up to 600 lb-ft of torque.

We Love to bolt on the horsepower, don't we? Oh yeah, we love it. But big power needs an equally strong driveline. If you're tracing the powerflow on its journey to the rear wheels, after the engine, the next stop is the clutch (or torque converter), then the transmission. And while we consider the clutch to be a wearable item, we often expect the transmission to last the life of the car. But anyone who's thrown a powershift or launched hard with regularity knows the feeling of a sheared gear, a worn blocking ring, a trashed input shaft, or a cracked case. In some instances, the factory warranty will take care of the repair, but you can forget about Ford picking up the tab if you've got a blower or other major modifications on there.

So, there comes a time in the course of every ambitious Mustang buildup when you'll consider upgrading the driveline to handle all of the power you've developed.

For Don Davis, that time was now. He'd just completed installation of a full Bassani exhaust, a Kenne Bell supercharger, and a few other choice goodies on his '04 Mach 1, and it was making plenty of power-over 440 at the wheels, according to the dyno. Now the objective was to strengthen the tranny.

Here are the goods: a Tremec TKO 600, a Spec Stage 2+ clutch, a flywheel and pressure plate, and the support parts. This is a pretty stout setup.

Don is the kind of guy who doesn't need to learn things the hard way, so he decided to dig in and replace his stock transmission before it turned into a mangled pile of steel and aluminum. He arranged for a new Tremec TKO 600 five-speed transmission, Spec Stage 2+ clutch, flywheel, and pressure plate to be installed by Need For Speed in Clearwater, Florida. Bruce Furtado, a journeyman technician, handled the installation.

The Tremec TKO 600 is a stout piece. It's popular among the Mustang crowd, where people want strength in a manual box, yet without giving up the benefits of having overdrive. The TKO 600 is a nice package in that it can stand up to the heavy-hitting torque and high transient loads. Tremec sells only to distributors, not directly to the public, but dealers like Need For Speed, D&D Performance, and Hanlon Motorsports can hook you up.

One wrinkle in this job is that the car already has subframe connectors, and that will require modification of the brackets supplied with the transmission. Tremec uses a longer, stronger crossmember that normally bolts to brackets attached to the subframes, but we're going to have a change of plans. Don't sweat it, we'll show you how it's done.