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Xtrac offer a range of customer in-line gearboxes to suit rear drive GT and Touring Cars with varying torque capacity requirements. The 427, 437, 545 & 559 gearboxes are a mid to high capacity configuration of high performance gearboxes, available to suit different installation requirements.

Xtrac have used their knowledge and experience gained in the field of endurance racing to produce this high quality yet cost effective range of gearboxes that shares common parts across the range. This enables spares to be both competitively priced and readily available.

Value engineered to meet strict cost constraints within this formula, this gearbox offers the highest quality at a cost effective price.


  • 800Nm (595lbf ft) maximum engine input torque*
  • 6 speeds with sequential gearchange selection
  • Aluminum L169 casings with ‘O’-Ring face sealing
  • 4 bolt front face or optional adaptor to suit Tilton Bellhousings
  • Accepts AP Racing clutch release slave cylinders
  • Range of Input drop gears
  • Gear ratios are straight cut integral 1st gear with slide on 2nd to 6th
  • Bell crank actuated gearchange rack reduces wear and improves gearchange performance
  • Lubrication via single stage eccentric lobe pump, configured for use with an external cooler
  • Temperature and pressure sensor bosses, dog ring inspection holes and oil fill and drain holes are provided, as is an oil breather fitting
  • Customer specific clutch shaft included
  • Various output flange option available
  • Single piece detent reverse lift cable is provided
  • Gearbox weight is approximately 36-38.5kg (79-85lb)*

The Gearbox Offers The Following Benefits

  • Light, positive sequential gearchange
  • Easily removable cluster for quick ratio changes
  • Cost effective, reliable solution

Options Summary

  • Super polished gear ratios (Xtrem Process)
  • One piece bellhousing to suit the customer’s engine
  • Gearchange potentiometer, mounting and display
  • Quick release detent cable
  • In car gear lever assembly
  • Magnesium RZ5 casings

Find out more

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