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The P386D gearbox is one of Xtrac’s legacy products, which whilst not currently in production, spares and technical support are still available upon request.

Xtrac’s P386D mid-engine longitudinal transaxle and has been developed from the highly successful and durable 386 Daytona gearbox and has been optimised for the GRAND-AM Daytona Prototype series but is well suited to all categories of Sportscar racing where performance and reliability are required.

Drive is fed from Daytona proven gear ratio’s mounted behind the axle centre line, through a final drive hypoid spiral bevel gear set, with a larger hypoid than the original 386 gearbox, allowing the engine to be mounted low in the car thus benefiting weight distribution without compromising drive shaft angles, or efficiency.

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


  • 5 or 6 speed sequential gear selection + reverse, sequence R,N,1,2,3,4,5,(6)
  • Highly serviceable ‘cassette type’ gear cluster Fully integrated pneumatic shift cylinder for AGS actuation.
  • 850Nm (625lbf ft) maximum engine torque
  • Dog clutch non-synchromesh engagement for forward gears and sliding mesh engagement reverse.
  • High efficiency hard cut hypoid spiral bevel pair
  • Stressed Aluminium L169 casing assembly with ‘o’ ring face sealing
  • Universal bosses for suspension/wing mounting
  • Single stage eccentric lobe, with dual pick-ups Recirculating system with external cooler
  • Bevel diff unit with plate and ramp type limited slip
  • A wide range of straight cut ratios are available
  • Oil level dipstick
  • Bevel gear and dog ring inspection ports
  • Clutch shaft to suit customer installation is included
  • Gearbox weight 77Kg (170lb)

The Gearbox Offers The Following Benefits 

  • Light, positive sequential gearchange
  • Quick change gear ratios
  • Low centre of Gravity
  • Cost effective, reliable solution

Options Summary

  • Super polished gear ratios (Xtrem Process)
  • Gear ground & super polished gear ratios & final drive (Xtrem Process)
  • Integral 1st and 2nd gear layshaft sets
  • Dog engaged reverse kit
  • Externally adjustable differential positive preload kit (nitrogen charged)
  • Adjustable negative preload differential conversion kit
  • High efficiency bearing kits
  • Bespoke suspension plate
  • Gearchange potentiometer, mounting and display
  • Manual shift, and mechanical reverse lockout
  • In car gear lever assembly

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