Sun Gear

The Sun Gear (Model SG-1012) is a precision internal transmission component designed for Bert transmission builds and high-performance automotive applications. This steel sun gear serves as the central rotating element within a planetary gear set, transmitting engine torque through a calculated mechanical advantage ratio. Whether you're rebuilding a Bert transmission for drag racing, street performance, or restoring a classic hot rod, the sun gear is a critical replacement part that directly impacts shift quality, power delivery, and overall drivetrain efficiency.

Manufactured from hardened steel, this sun gear withstands extreme rotational forces and meshing loads inherent to performance driving. The gear's tooth geometry is engineered to mesh perfectly with the planet gears and ring gear within the transmission housing, ensuring smooth power transfer and minimal backlash during acceleration and deceleration events. At 0.84 lbs with compact dimensions (3.65 x 1.65 x 5.2 inches), the sun gear is lightweight yet rigid enough for high-RPM operation. The precise manufacturing tolerances are essential for minimizing wear on mating components and maintaining the transmission's rated torque capacity over repeated driving cycles.

This sun gear is essential for anyone rebuilding or servicing a Bert transmission system used in performance vehicles, street rods, or competition builds. Mechanics and transmission specialists rely on OEM-quality replacement gears like the SG-1012 to restore proper engagement and eliminate worn tooth damage that causes slippage or harsh shifting. Installation requires removal of the transmission from the vehicle and disassembly of the planetary gear set; this component should be paired with matching planet gears and ring gears to ensure harmonized wear characteristics. Proper assembly with correct preload and end-play settings is critical for long-term reliability and performance.