SEMA 2025: Tremec Unveils C8 Corvette Manual Transmission

In a performance landscape dominated by advanced driver aids and lightning-fast dual-clutch gearboxes to achieve the best acceleration figures and lap times, the manual transmission has become an endangered species. But Tremec isn’t letting three-pedal driving fade quietly into the sunset. This year at the SEMA show, the company revealed its boldest enthusiast-focused project in years: a fully engineered 6-speed transaxle to make the C8 Corvette manual transmission that GM refuses to produce.

Strolling through the Las Vegas Convention Center, the billet-aluminum gearbox on display initially looked like a familiar Tremec TR-9080 DCT pulled from a production C8. The shape, mounting points, and overall dimensions were visually identical. But a closer look confirmed it was something entirely new. An H-pattern 6-speed C8 Corvette manual designed to drop into the mid-engine Corvette chassis while giving drivers the analog engagement the factory never offered.

The casing mirrors the factory 8-speed DCT in size and mounting geometry, but the internals mark a major departure. Tremec sourced 2nd through 6th gears, along with the final drive and ring-and-pinion ratios, and mechanical LSD, from the non-Z51 DCT for durability. The 7th or 8th gearset was left on the table, and 1st gear has been revised to a taller ratio to better support high-horsepower launches. The input shaft traces its lineage to Tremec’s stout Magnum 6-speed, a favorite in high-power builds.

Tremec claims the new C8 Corvette manual transaxle is engineered to handle up to 1,000 horsepower, 800 pound feet of torque, and engine speeds up to 8,600 rpm, which are serious numbers that put it well beyond a novelty swap. Still, the company insists this transmission is intended strictly for the aftermarket, not as a factory Corvette option. And for now, builders will be responsible for integrating their own clutch pedal assemblies and shifter solutions, as Tremec does not plan to offer a full conversion kit.

Even so, the message is clear: for modern Corvette owners who crave a more visceral connection to their car and build their own C8 Corvette manual car, Tremec just cracked open a door everyone assumed GM had welded shut.