GM TH400 racing applications quickly push the heavy, cast-iron OE forward drum over its limits. To dramatically reduce weight and deliver the ultimate in reliability and transmission performance, #Sonnax introduces this new heavy duty forward drum — a high-strength, chromoly steel upgrade just 3 oz heavier than a common aluminum drum. 💪💪 Watch this video to get a full breakdown of all the race-ready features, plus the heavy and extreme duty input shaft options for a complete Sonnax build. Clic