The GPM SLA1337FS front differential gear set is precision-machined from 20Cr carbon steel and treated with a hardened black finish to extend service life under heavy loads. The spiral helical tooth profile reduces impact loads at tooth engagement and promotes consistent torque transmission for front-driven axles. This kit replaces softer stock gears and is intended for hobbyists seeking a durable, upgrade-level steel solution that maintains gear alignment and reliability in high stress running.