The options are many for upgrading the Forward drum on TH400 racing transmissions. Sonnax–the leader in transmission innovation–now offers a high-strength, light weight drum to guarantee racers at any power level the ultimate in performance.

For radically improved durability and reliability, the heavy duty Sonnax drum is manufactured from chromoly steel with many unique lightening features. It weighs 3 lbs. less than the OE drum and is just 3 oz. heavier than a common aluminum drum—a soft material with huge wear issues. This means racers seeking enhanced performance don’t need to switch to an aluminum option for reduced weight. Additional features like an oversized, 28-tooth spline at the connection between drum and shaft, a high RPM checkball and unique clutch improvements make the Sonnax drum an ultra-modern upgrade for any TH400 build.

Heavy duty forward drum 34554-01 can be used with a variety of input shaft styles, including the Sonnax 1" dia., 30-spline heavy duty input shaft 30280-02 or 1-1/8" dia., 35-spline big input shaft 35280-02. Learn more about the drum and other Sonnax components at http://www.sonnax.com.