T56 Magnum Transmission GM LS

The T56 Magnum Transmission GM LS is the modern standard for LS engine swaps and high-performance builds demanding a bulletproof six-speed manual platform. Built by TREMEC, this transmission pairs with LS-series engines to deliver smooth, reliable power transfer across street, strip, and road course applications. Whether you're restoring a classic with contemporary muscle or building a modern performance vehicle, the T56 Magnum handles both daily driving and sustained boost loads without compromise.

This unit features TREMEC's proven helical gear design and optimized internal geometry, engineered to maximize efficiency while minimizing parasitic losses in the drivetrain. The six-speed layout allows taller cruising gears for highway fuel economy while maintaining aggressive ratios for acceleration and launch control. At 160 pounds and measuring 19.5 × 15.5 × 39.5 inches, the T56 Magnum offers a compact footprint suitable for tight engine bay configurations without sacrificing structural rigidity or cooling performance. The transmission is fully adaptable to both carbureted and fuel-injected LS mills, with straightforward bolt-pattern compatibility across a wide range of LS variants.

Builders and enthusiasts favor the T56 Magnum for its proven durability under extreme conditions—from turbocharged and supercharged applications to heavy-duty towing scenarios. It integrates seamlessly with modern electronic shift indicators and factory LS engine management systems, eliminating the need for proprietary adapters or workarounds. Installation pairs well with factory or aftermarket bellhousings, making this transmission the go-to choice for anyone serious about LS platform reliability and performance without sacrificing everyday usability.