Hi, I'm sure you're correct and thanks for the advice. Actually I was only relaying published information and mentioned Castrol because another person raised the brand. I've always respected Castrol though.
My interest in the subject is due to my desire to change my R33 GTR gearbox oil soon. I will survey the market technically but I don't want to stray from Nissan's guidelines or spend unnecessary amounts on gearbox oil since my vehicle never goes on the track. However it is used on very cold winter mornings (if it's not raining)!
I still can't believe what some members spend on wiper blades and I'm not tight when it comes to proper car maintenance.
PS, I wonder how many owners have got the V-Spec diff oil wrong?
It's tricky with cars like yours as there are many options you can in theory use, but often there are a few things that are well proven. The Redline or Amsoil gear oils are very good, not cheap, but according to the specs for a Skyline you should be able to use a cheaper oil as long as it meets the GL4 specification. The problem with that is that many of the cheaper oils meet the GL4 and GL5 specs, and that can mean the gear changes aren't as smooth as the synchros don't get slowed down enough. If you want to go for a cheaper gearbox oil, it may be best to go for something very basic, like the Fuchs Gear Syn, as it's not as good a lubricant and should slow the synchros sufficiently. The problem with that though is that firstly it's not as good at protecting the gears and secondly, you need to change it more often, making the use of a cheaper oil a bit pointless as the total cost soon adds up to the price of the good stuff, which will outlast it. If you have the spare cash, go for one of the better oil and forget about changing it for a long time, or if not, go for a basic one and be prepared to change it again.
Cheers
Tim
