Sonnax
Motor Vehicle ManufacturingVermont, United States51-200 Employees
Sonnax Transmission Company designs, manufactures and distributes drivetrain components for the automotive aftermarket, commercial vehicle sectors and related industries. As part of Marmon/Berkshire Hathaway, it operates the Sonnax and Rostra Powertrain Controls brands and integrated with Rostra in 2021 to form a single, transmission-focused organization. The company emphasizes root-cause problem solving and uses new materials and testing to restore OE performance or improve beyond it, and it holds ISO 9001:2015 certification. Headquartered in Bellows Falls, Vermont, Sonnax maintains production in Laurinburg, North Carolina, and technical development centers across California, Georgia, Indiana, Missouri and Wisconsin. The firm serves the automotive aftermarket and commercial vehicle operators seeking reliability and performance improvements in transmissions and converters. Recent product introductions include servos for GM TH400 and 4L80-E transmissions and other kits designed to address root causes of common failures, reflecting ongoing focus on durable, consistent performance.