The options for upgrading the Nissan GR6 gearbox are vast and very much depend on the intended use of each customer. Litchfield have been the UK's Authorised Dodson Motorsport distributor since 2011 and have invested in one to one training for our technicians so we have a complete understanding of the gearboxes systems, strength and weaknesses. Below are some of the most common upgrades we can offer in-house.
The first upgrade available for the GT-R GR6 gearbox is to update the control ecu software. This will be the latest Nissan software suitable for your vehicle, including the most recent revision of the launch control software, along with the many any improvements from Litchfield, Nismo and Ecutek. It will vastly improve driveability on the pre-2011 GT-R and is an integral part of our performance mapping and additional safety features. The gearbox software costs £250 +vat, with further updates are free when the car is serviced or tuned by us.
2. Solenoid caps
Not to be confused with circlips, the fitment of solenoid caps is absolutely imperative into the pre-2011 GR6 gearboxes and actually formed part of a recall on the US models . The 2011+ Nissan GT-Rs were fitted with these clips as standard and, as a result, the cars do not tend to suffer the same problems. We fit these new caps along with stronger filter magnets and a new genuine sump gasket. Although it is cheaper to fit these when you have a gearbox oil change, we would suggest immediate fitment as a preventative measure. Many of our gearbox repairs are due to issues experienced due to spun solenoid pistons, prevented by fitting the caps.
3. Clutch upgrades
When going for large BHP and high torque levels in GT-R engine builds, clutch upgrades must be taken into account. Very high levels of torque can cause the standard clutches to slip and will eventually wear out. We therefore recommend upgrading the clutches to the Dodson / Exedy alternatives based on the amount of torque being produced. These clutches along with stronger seals and springs will ensure the GR6 gearbox continues to work perfectly despite the extra power: SuperStock - rated at 650lbft, Sportsman 8 Plate Clutch Kit - rated to 800 ft/lbs; Promax 10 Plate Clutch Kit - rated to 1000 ft/lbs. We are also able to upgrade the 4wd clutch and supply billet clutch baskets. Please call us for pricing as the specification will depend on your application.
4. Dodson First gear shaft
Dodson Motorsport Extreme Duty 1st gear kit, For upgrading the First Gear and input shaft in your GR6 transmission. The First Gear Kit includes Dodson 1st Gear, Dodson Input Shaft with Sleeve Bearing, Shaft Plug and Mechanical Circlip, Kit includes Gear lock, 2/4/6 thrust bearing circlip and a Dodson Mechanical Circlip 2.0mm. Dodson 1st Gear Kit retains a smooth feel and a quiet shifting. We would recommend this as an initial upgrade on your gearbox if you are running a more powerful non-standard 'Built' engine and thus far seems capable of strengthening the gearbox for upto 700lbft of torque.
5. Full gearset with Overdrive
Extreme Duty Gearset in Overdrive ratio for the GR6 Transmission with Straight cut 3rd and 4th gears. Full 1-6 Gearset including 2/4/6 cluster and Input Shaft. Gearset Includes: Dodson 1-6 gears (Overdrive 6th), Dodson Straight Cut Cluster (Overdrive 6th), Dodson Input Shaft with sleeve bearing, Dodson Mechanical Circlip & Shaft Plug. Dodson Extreme Duty HDSFB 35 selector fork and Selector Shaft, Dodson Gear Lock, Dodson Circlips (thrust bearing circlip 1,3,5 / 2,4,6. Dodson Motorsport Park Paw, Dodson Cluster Bearing, Dodson Output Shaft End Float Shim, proven on the fastest GT-Rs in the world and complete gear solution.
6. Further transmission upgrades
Litchfield are able to supply and map the excellent KAPS 4wd control unit. This control ecu allows the driver to select from four pre-determined maps created by us to change the transmission characteristics. We can tailor the maps for your application - drag, track, rwd only for example.
The front differential can be changed to a Quaife Auto Torque Biasing unit from the standard open version, improving grip, handling and steering feel. More information can be found on it's dedicated page here.
Externally Litchfield produce a billet aluminium transmission strengthening brace. The brace is only really required on high-power drag or sprint car applications to reduce the high-load torsional flex in the rear differential casing, although can be fitted to any R35 GT-R.