Gearstar Performance

Custom Transmission Build Team

torque converter matching
dyno testing
transmission installs
GM performance automatics
Ford performance automatics
Mopar performance automatics

Gearstar Performance Transmissions has been hand-building high-performance automatics in Akron, Ohio since 1996. Every unit is assembled start to finish by one builder, matched to the customer's engine, gearing and intended use, then dyno-tested before it ships. The build team writes here about transmission specs, install procedures, torque converter matching and what actually holds up behind real power.

Preventative maintenance with your transmission

Gearstar Performance December 5th, 2025 2 minute read

Transmission Slip Yoke and measurements

Gearstar Performance December 5th, 2025 2 minute read

GM Torque Converter: Unlocking Power and Efficiency

Gearstar Performance February 26th, 2025 6 minute read

Upgrade your project car with a rebuilt GM torque converter for unmatched power and efficiency. Learn how custom stall speeds, billet components, and...

Ford AOD Valve Body: Key to Optimizing Your Transmission

Gearstar Performance February 19th, 2025 5 minute read

The Ford AOD transmission is a stalwart of classic muscle cars and trucks, but its stock valve body – the “brain” controlling gear shifts and fluid flow...

Enhance the Performance of a Ford AOD Transmission Pan

Gearstar Performance February 11th, 2025 6 minute read

The Ford AOD (Automatic Overdrive) transmission is a workhorse, powering classic Mustangs, Crown Victorias, and F-150s for decades. But if you’re pushing...

Choosing the Right Upgrade for a Turbo 350 Transmission Pan

Gearstar Performance February 3rd, 2025 6 minute read

The GM TurboMatic 350 (TH350) is a legendary transmission, powering classic muscle cars, hot rods, and project vehicles for decades. But if you’re...

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