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The Automobile Club de l’Ouest (ACO) and International Motorsports Association (IMSA) have announced that Xtrac will be the sole gearbox supplier for the new Le Mans Daytona hybrid race category known as ‘LMDh’.   The ACO and IMSA together have unified this innovatory top-tier for both the WeatherTech SportsCar Championship in the USA and Fédération Internationale de l’Automobile (FIA) World Endurance Championship (WEC).

“It’s a visionary hybrid transmission built on years of experience gained by operating at the highest level of motorsport,” says Xtrac chief executive Adrian Moore. “Prototype gearboxes will be available from mid-2021 for hybrid system testing”.

The P1359 gearbox developed for the new LMDh class is a 7-speed transverse arrangement with an integrated motor-generator unit (MGU) driving into the gearbox through an optimised gear train.  The integration of the hybrid system is a vital attribute of the LMDh specification.  Xtrac has worked closely with the ACO, IMSA, Bosch and Williams Advanced Engineering (WAE) to ensure that the package, function, and overall operation is optimised for cost, weight, performance, and reliability.  Bosch is supplying the MGU and hybrid control system, while WAE is supplying the battery system.

The new LMDh class has been created by the convergence of ACO and IMSA regulations to provide a cost-effective, high-performance car able to race in the WEC series as well as the IMSA sportscar championship in the USA.  This cost capped sportscar will also share a common spine consisting of the complete car less the bodywork, engine, and hybrid system with the next generation LMP2 sportscar.


  • Designed for the new ACO-IMSA LMDh technical regulations
  • 7 speed sequential using Xtrac’s pneumatic integrated valve actuator (IVA) gearchange system
  • Transverse three shaft architecture
  • Structural casings supporting suspension, rear impact structure & wing, air jack and wheel tethers
  • 585kW maximum combined input power
  • 6,500 to 10,000 input RPM
  • Bosch 50kW MGU in P2 position
  • Gear drive from MGU to gearbox input with a range of ratios to match MGU speed to engine speed
  • Limited slip plate differential with externally adjustable gas charged pre-load
  • Integral output flanges to suit 38mm diameter tripode joints
  • Semi dry sump recirculating oil system with internal baffles and externally accessible oil filters
  • Integral 3 litre engine oil catch tank with level sensor, fill, drain and sight glass ports
  • Torque sensing driveshaft and speed trigger mounts
  • Floor mounts and scrutineering datum pad
  • Lightweight magnesium RZ5 maincase housings and side cover castings
  • Gearbox weight 78kg / 172lb (including MGU drive gear train, but excluding MGU)


  • Fully form gear ground and Xtrem super polished gear ratios including bevel and final drive
  • Integral 1st and 2nd layshaft, 3rd to 7th slide on with a wide range of ratios available
  • Easily removable cassette cluster for maintenance and ratio changes
  • Externally adjustable limited slip differential
  • Bespoke clutch shaft to suit customer installation
  • Design based upon the existing P1159 gearbox used in current LMP1, LMP2 and DPi with proven reliability and race winning pedigree
  • World renowned customer service from Xtrac in the UK and the USA, including minor and major rebuilds at designated service intervals
  • Common gearbox for the next generation LMP2 class with a non-hybrid version of the same gearbox


  • Casing material in Aluminium L169
  • Alternator drive and mounting
  • Air conditioning drive
  • Bell housing
  • Clutchshaft torque sensor
  • Starter ring gear
  • Major and minor rebuild kits
  • Driveshaft assemblies; torque sensing and non-torque sensing available

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