Yesterday we put up a post about How to Fix the GR6 Transmission.
It seems that some guys in Australia have already developed a gearoil and are currently testing it in their car. They were not able to purchase the factory GR6 gearoil, so they had the factory fluid analyzed and had their own oil blended.
First up, Nissan are not joking when they ask you service the transmission oil in 1800 miles of hard use. The light green fluid that we sampled from the transmission had a distinct burnt smell (like burned auto transmission fluid) and had visible grey metallic infusion in its makeup. This is probably to be expected from a new transmission, but taking no chances we sent the sample off to a laboratory that specialises in oil analysis for a complete inspection. The first report was a conventional Spectrograph which showed that there could be a potential lack of lubrication in the transmission with 200 micron sized particles of gear material in the sample.The GR6 uses a dry sump oiling setup. Maybe the fluid they are using just is not able to stay where its needed to cool and lubricate the gears under high loads.
R35 transmission oil is a specialist product, not an off the shelf D-Matic or Transmax ATF. A conventional ATF will in fact - from our knowledge of the chemistry - cause problems with the dual wet clutches. This is the 'key' to R35 transmission oil, keeping the clutches happy and healthy with a nice slick action, which is why Nissan have sacrificed lubricity and metal protection in the quest for the very best shift action and 'driver comfortable' clutch engagement.
Another 1800 miles have been completed with our new lubricant in place, and so far we have some interesting yet expected test results. The initial feedback was one of markedly reduced transmission noise particularly in first and second gear where you normally hear some light whine. The solid boundary lubricant does this, it also reduced internal gearbox friction to the point where the shifts (particularly second gear - which needs it!) feel a little softer. Noteably less ratcheting and banging sounds come out of the transmission - put a 'Chassis Ear' on the gearbox and drive sometime you will be amazed at the mechanical symphony going on in there! Another benefit of using a Solid Boundary lubricant is that it gives a margin for shock absorbtion in the transmission....no guarantees it will make any LC gearbox problems go away, but using this kind of lubricant is accepted in industry as being a gear protectant in high shear conditions