R34 GT-T Gearbox Oil Differences?

[R34NeoLover]

Hi all, so i ordered an npc organic clutch and flywheel, rang up Nissan to see if they had any genuine oil for manual 5 speed gearbox, they said the stock oil is castrol vmx 75-80 or vmx 75-90. I am now confused, which exactly is the standard one and what is the difference between the two? I know theres previous threads discussing using redline lightweight shockproof, but from what ive read, this is for worn synchros? I cant tell the exact condition of my gearbox, but it shifts into every gear smoothly, so thats why i was thinking of using the standard oil, unless its suggested otherwise?

[GTSBoy]

75-80 refers to the viscosity of the oil in "winter" and "summer" respectively. It's a multi-grade oil that changes its apparent viscosity with temperature. When its cold, it acts as if it's a little thinner (the 75) and when it is hot it acts as if it is a little thicker (the 80).

The other oil has a wider difference between cold viscosity and hot. So which one you use might depend on where you live and/or how the car is used. If you live in a cold part, you might use the 75-80. If you live in a hot part or the engine and gearbox get driven hard for extended periods (and so dump a lot of heat into the oil) then you might choose the heavier oil.

As you say, if your box is in good nick, there's no need to put shockproof in it. Just use the VMX.

Edited August 2, 2019 by GTSBoy
bluddy typos

[R34NeoLover]

1 minute ago, GTSBoy said:

75-80 refers to the viscosity of the oil in "winter" and "summer" respectively. It's a multi-grade oil that changes its apparent viscosity with temperature. When its cold, it acts as if it's a little thinner (the 75) and when it is hot it acts as if it is a little thicker (the 80).

The other oil has a wider difference between cold viscosity and hot. So which one you use might depend on where you live and/ore how the car is used. If you live in a cold part, you might use the 75-80. If you live in a hot part of the engine and gearbox get driven hard for extended periods (and so dump a lot of heat into the oil) then you might choose the heavier oil.

As you say, if your box is in good nick, there's no need to put shockproof in it. Just use the VMX.

Ah beautiful, just what i was looking for. Yeah the car is used mostly as a weekender and i do a few track days a year in it, so looks like 75-90 is definitely the way to go, thanks