Agustin Jimenez
Technical Editor
September 3, 2015
Photos By: Courtesy of Ford

It’s no secret that the new Shelby GT350 Mustang is one hell of a steed and with a 100hp per liter being produced by the flat-plane crank 5.2L V8; it’s the most powerful naturally aspirated production engine that the Blue Oval has ever offered. Of course, with all this newfound power comes the need for much stronger components that can keep up with the demands of the high-revving engine under the hood. With a redline of 8,250 rpm and 526 horses on tap, a new transmission was needed to safely put the power to the ground.

The new six-speed transmission in the Shelby GT350 is much lighter and stouter than the gearboxes that were offered on previous Mustangs. The high-revving 5.2L engine is paired with the incredibly strong Tremec TR-3160 six-speed manual transmission. The unit has been heavily revised for Shelby GT350 to handle the high engine speeds as well as the rigors of long and brutal track duty. The transmission also provides the kind of precision engagement, smoothness, and reduction in weight and rotating inertia demanded by Ford Performance.

Almost every component received special attention to ensure durability and improved shifting performance while extreme measures were taken to ensure a positive feel as well as durability. Some of these measures include power-honed gears, air-to-oil transmission cooler and even carbon-bronze triple-cone synchronizers.

The core of every transmission is its gear set. Each gear in the TR-3160 rides on a gun-drilled main shaft that reduces weight, and has been power-honed in a post-heat-treating operation for a reduction in gear lash and enhanced smoothness to reduce noise, vibration and harshness. The sides of the gears are milled to remove unstressed material and reduce weight – resulting in “I-section” gears. Specially formulated carbon-bronze triple-cone synchronizers are engineered to deliver the feel of a bronze synchronizer with the heat capacity of carbon, which is a key attribute in racing situations.

A dual-mass flywheel with a dual-disc clutch mates the engine with the gearbox to get the power to the ground. The dual-mass flywheel enhances engagement smoothness, reduces noise, vibration and harshness, and allows for the elimination of damping springs in the hub of the clutch – which in turn means a lighter, smaller-diameter clutch and reduced rotating mass. These two components are rigidly mounted in a die-cast clutch housing optimized for compactness and stiffness. This combination allows for incredibly quick shift times which will no doubt make the GT350 much faster around any track.

Precision gear selection is accomplished via a lightweight shifter mechanism in an aluminum housing. The mechanism uses low-friction main pivot-ball and shifter-linkage joints, which enable low effort shifts with very short throws. Aggressive shift rail detents provide the driver with satisfying, positive shift engagement.

The transmission mechanism resides inside a custom clutch housing, and the rear extension housing is shortened and optimized for stiffness and weight. A 3.2-inch center-to-center distance allows for high torque capacity with a very small package and footprint. The compact and stiff nature of the transmission reduces weight and improves the noise, vibration and harshness qualities of the overall driveline.

Every aspect of Shelby GT350 is built for track capability, and the transmission is no exception. Managing temperatures and ensuring sufficient lubrication is key to real-world track durability. The GT350 Track Package and GT350R have a unique oil-to-air transmission cooler that is fed by a gerotor pump integrated into the housing of the transmission. This arrangement ensures the transmission stays cool and properly lubricated when romping around a track, but it also brings the added benefit of keeping transmission heat out of the coolant circuit. This means the radiator is fully dedicated to engine cooling, which means it can have a smaller and lighter design.

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The air-to-oil transmission cooler is mounted directly behind the front fascia with its own dedicated ducting. Significant aerodynamic work was done to perfect the cooler angle and duct shape to ensure airflow is distributed over the entire face of the cooler for maximum efficiency. Finally, a sensor is included in the transmission to warn the driver via the gauge cluster of an overheat condition, in the very unlikely event a driver might overwhelm the cooling capacity of the transmission.

As you can see, it’s not just about building a stronger transmission. When it comes to all-out track performance, the transmission can mean the difference between a winner and a loser. Everything about the Tremec TR-3160 six-speed manual in the GT350 and GT350R screams performance and it’s easy to see why it was deemed the perfect piece to back up one of the coolest Shelby Mustangs to ever be offered by Ford.