Which Oil for my Manual Gearbox GQ

[Bloodyaussie]

***** MODERATORS NOTE *****

I have copied this out of BA's Members ride thread because it is useful and will get lost there.

Thanks Matt, George and Craig. Good info.


Having gearbox trouble.

Not sure which way to go as it can be very expensive to rebuild a gearbox but I am having no luck with second hand of late????

I dont want to leave it too long as there is a brand new Ci clutch in there and I am worried it will turn to shit with oil getting on it.... hmmm

[nissannewby]

Yeah Roofy the last time I was this broke was when I was supporting my mum about 5 years ago... paid her rent for a year, killer !!!

We will work through it though.

Not sure which way to go as it can be very expensive to rebuild a gearbox but I am having no luck with second hand of late????

I dont want to leave it too long as there is a brand new Ci clutch in there and I am worried it will turn to shit with oil getting on it.... hmmm

Why do you need to rebuild the box?

If there is oil in there mate I would be wanting to repair it as soon as possible cos if the friction plate becomes oil impregnated then it will need to be replaced. Also are you keeping an eye on the oil levels so you know exactly where it's leaving from?

[Bloodyaussie]

This box bites.... mainly 2nd gear and it also drops out of third and its own.

Still working out the best options now as this is all new.... I took a punt thinking that the box had done half the km's mine had done so thought I would be on a good thing, I was wrong and right??

My old box has a noisy 5th plus can be hard changing gear mainly in 4wd and also a very noisy bearing (George knows which one) as the one in there now has no bearing noise.

In trying to save a dollar I end up spending more.... lesson in this folks!!!!

[nissannewby]

What oil are you using?

[Bloodyaussie]

I would have to go outside and its cold and wet.... the bolts in my neck might rust???

[nissannewby]

I would have to go outside and its cold and wet.... the bolts in my neck might rust???

Why is everything a question? If your worried about rust put some of the oil on them while your out seeing what it is lol. You need to make sure the oil is a gl-4 oil.

[Bloodyaussie]

I cannot be 100% sure as I have done a big clean up and cannot remember if I used something else or if I did use the bottle of Castrol VMX80

My socks are wet!!!

[mudnut]

So, gl-4 as opposed to gl-5 is still an issue, Matt? That could be the reason my other box failed because Nulon reckoned their gl-5 oil was the one for my RB30 gearbox, and I used it.

[nissannewby]

I cannot be 100% sure as I have done a big clean up and cannot remember if I used something else or if I did use the bottle of Castrol VMX80

My socks are wet!!!

Who goes outside in just socks :p no wonder why your cold.

[nissannewby]

So, gl-4 as opposed to gl-5 is still an issue, Matt? That could be the reason my other box failed because Nulon reckoned their gl-5 oil was the one for my RB30 gearbox, and I used it.

Gl-5 is ok but the synchros in the Nissan box behind the 4.2 ( petrol and diesel) and the 3.0 diesel (all the same box) much prefer the gl-4 oil. I cannot comment on the box behind the rb30 mate but if the manual specifies gl-4 then this is what I would be using.

I changed from a gl-5 to a gl-4 oil in my patrol and noticed the difference nearly straight away. My box had dramas down shifting to 4th from 5th and also 4th to 3rd once the gl-4 oil went in this has probably gotten 50% better. I don't think it will get better as the damage may have already been done prior to me purchasing the vehicle but alls I changed was the oil.

[mudnut]

So which brand did you use? As I have to double clutch into 2nd when the box is cold.

[nissannewby]

Hi-tech oils mate.

[mudnut]

I will ring the mech who did the change out, and see if he can tell me if he used gl-5. Thanks, Matt.

[nissannewby]

I will ring the mech who did the change out, and see if he can tell me if he used gl-5. Thanks, Matt.

Does it specify gl-4 for the rb30 box?

[mudnut]

Sorry for the delayed answer. The original owners manual specifies GL 4 one of the after market manuals reckons 4 or 5

[Alitis007]

Gl-5 is ok but the synchros in the Nissan box behind the 4.2 ( petrol and diesel) and the 3.0 diesel (all the same box) much prefer the gl-4 oil. I cannot comment on the box behind the rb30 mate but if the manual specifies gl-4 then this is what I would be using. I changed from a gl-5 to a gl-4 oil in my patrol and noticed the difference nearly straight away. My box had dramas down shifting to 4th from 5th and also 4th to 3rd once the gl-4 oil went in this has probably gotten 50% better. I don't think it will get better as the damage may have already been done prior to me purchasing the vehicle but alls I changed was the oil. The difference between gl4 and gl5 is the synthetic additives in the oil, gl5 has more that gl4 so unless the viscosity is different how does less friction modifiers make your synchro's mesh easier ??? I'm pretty sure the gu gear box uses a straight 75w oil but can't remember if the gq uses a 80w90 or a 75w aswell

[mudnut]

When I did the gearbox oil change last year, before it died, I researched the issue. Apparently early on, when gl5 oils were first released, the gl5 additives that coat and attach to the synchros are stronger than the brass. When they are worn off, they take a small proportion of the brass with them. I was assured by Nulon that the problem had been rectified with more modern oils. But now I'm not so sure, so I will have to shell out for the gl4.

[nissannewby]

The difference between gl4 and gl5 is the synthetic additives in the oil, gl5 has more that gl4 so unless the viscosity is different how does less friction modifiers make your synchro's mesh easier ??? I'm pretty sure the gu gear box uses a straight 75w oil but can't remember if the gq uses a 80w90 or a 75w aswell

It's well documented across these sorts of forums. It just seems the materials used in the boxes I mentioned earlier prefer the gl4 and I was just passing on my experience with the two different oils. Some additives in the gl-5 can attack yellow metals (brass,copper etc) which could possibly shorten the life. If it specifies gl-4 oil then why use something else? . Sometimes you can have to much of a good thing and it may be the case with the newer gl-5 classification.

[Alitis007]

When I did the gearbox oil change last year, before it died, I researched the issue. Apparently early on, when gl5 oils were first released, the gl5 additives that coat and attach to the synchros are stronger than the brass. When they are worn off, they take a small proportion of the brass with them. I was assured by Nulon that the problem had been rectified with more modern oils. But now I'm not so sure, so I will have to shell out for the gl4.
It's well documented across these sorts of forums. It just seems the materials used in the boxes I mentioned earlier prefer the gl4 and I was just passing on my experience with the two different oils. Some additives in the gl-5 can attack yellow metals (brass,copper etc) which could possibly shorten the life. If it specifies gl-4 oil then why use something else? . Sometimes you can have to much of a good thing and it may be the case with the newer gl-5 classification.

Cheers guys! I know with new diesel motors the friction modifiers affect the particulate filter but didn't realize it had that sort of effect on the synchro's aswell

[MudRunnerTD]

I have copied this out of BA's Members ride thread because it is useful and will get lost there.

Thanks Matt, George and Craig. Good info.

[Bloodyaussie]

And thanks to me for all my greatness !!!!!!!!!!!!!!