No one knows transmissions & torque converters like

Sonnax designs, develops and manufactures the highest quality aftermarket automotive products. We are the world’s largest full-line supplier of torque converter parts, and offer transmission and specialty driveline components through a global network of parts distributors.

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Latest News

March 20, 2024

Top Shop Product Winners of 2024

Every year, Transmission Digest accepts nominations for the top products and tools in the powertrain aftermarket. Readers vote for their favorites to determine the winners.

The results are in: we won 9 top product awards! Thank you all for your trust and support of Sonnax and Rostra products – we couldn’t have done it without you.

Take a look at the winning products here:


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December 14, 2023

Sonnax Holiday Hours

Heads up! We’re taking a few days off for the holidays to spend treasured time with our families and enjoy the holiday cheer.

Sonnax will be closed:

  • Dec. 22
  • Dec. 25
  • Dec. 29
  • Jan. 1

Thank you for all your support. Wishing you a happy, healthy and prosperous New Year!

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October 13, 2023

Rostra Adds 13 OEM/S Solenoids & Modules

Sonnax Transmission Company is excited to announce the addition of 13 solenoids and modules to the Rostra Powertrain Controls product group beginning this October. The company has secured these SKUs in an agreement to succeed BorgWarner as the distributor for their OE solenoid supplier, Solero Technologies.

This distribution program represents an important opportunity to support the Sonnax mission: to be the leader in bringing innovative, high-quality drivetrain components to the automotive aftermarket. 

Look for this icon at to identify authentic OEM/S parts supplied by Rostra and contact your distributor today!


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Join an exciting front-line team focused on developing and delivering the best products in the industry, a team whose imagination, hard work and results are rewarded.

After decades of serving the transmission aftermarket as standalone companies, Sonnax and Rostra Powertrain Controls integrated in 2021 to become a single, transmission-focused organization.

Our 200+ employees proudly serve the automotive aftermarket with the Sonnax and Rostra Powertrain Controls brands, and strive to further the company’s reputation for excellent service, technical knowledge and customer dedication.

Sonnax Transmission Company headquarters is in Bellows Falls, Vermont, with production facilities in Laurinburg, N.C. and technical development centers in California, Georgia, Indiana, Missouri and Wisconsin. Rostra Powertrain Controls’ production facility is in Laurinburg, N.C.

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