Sadev launches six-speed gearbox for the Ligier JS2 RS

Sadev, French transmission manufacturer, has developed a new six-speed sequential gearbox for the Ligier JS2 RS.

Launched yesterday at the Professional MotorSport World Expo in Cologne, the new gearbox incorporates a redesigned casing, upgraded lubrication system and optimised gearsets to meet the demands of GT and endurance racing.

The SL90-20LW represents the latest evolution of Sadev’s SL90 transmission platform.

Developed using advanced calculation and simulation tools, the new transmission features a revised casing architecture and improvements to the efficiency of its lubrication system.

Sadev has also optimised the gearsets and revised the available gear ratios, with the changes intended to improve durability, performance and reliability.

Central to the design is an integrated oil pump providing directed, pressurised lubrication to the gears and bevel gear. The gearbox uses straight-cut gears with dog engagement, manufactured from high-strength carburised steel. The gear teeth feature optimised ground profiles, while internal components undergo shot peening to improve their resistance to fatigue.

The six-speed transmission also incorporates a limited-slip differential using a six-disc ramp-and-plate arrangement, with preload controlled by Belleville washers. Interchangeable gear ratios allow the transmission to be configured for different racing applications, while reverse gear can be operated through a cable or solenoid lockout system.

The redesigned casing is manufactured from AS7G aluminum, with O-ring sealing and an assembly using spacers and studs. The complete gearbox weighs 74kg, including the input shaft, and is rated to handle 700Nm of torque in its Ligier application.

Precision inspection of transmission components at Sadev’s manufacturing facility.

The SL90-20LW has been selected for the Ligier JS2 RS, a GT race car powered by a 3.5-litre Ford EcoBoost V6 producing up to 650hp. Built around a dedicated carbon-fibre monocoque, the car combines a MoTeC engine control unit, Bosch ABS, traction control and Brembo endurance braking system.

Sadev says the transmission’s latest developments are designed to improve operating efficiency and reliability while maintaining manageable servicing requirements and running costs.

The new gearbox also continues a technical partnership between Sadev and Ligier spanning more than 25 years. Their collaboration began with the Formula Renault Campus single-seater in the early 2000s and has since extended across Formula 4, Formula 3, sports prototypes and GT racing.