How do you keep the GU's 5sp shifting smooth as butter?

Problems seem mostly gone now with the Penrite. It isn't entirely as buttery smooth as the first day I drove it, but I suppose road tripping 2000+ k's through rural NSW in rough conditions on GL-5 gear oil likely did some type of permanent damage to the synchros. It isn't perfect, but it's back to registering somewhere on the enjoyable scale at least.

As luck would have it, while the Nissan service center had my vehicle, I found and bought Penrite GL-4 75W-90, the perfect stuff. Ran back to Nissan but they told me they had already changed out the gear oil.

Quote:

---

Originally Posted by mudnut

I hope the GL4 plus is not just a GL5. I had the same problem with shifting after my gearbox was changed out. I asked the mechanic which oil he used, and it turned out to be GL5.

---

I called up Penrite about their "GL-4 plus" rated product. The techie I spoke to over the phone explained it's essentially a GL-4 which substitutes out mineral oils for synthetics to improve anti-foaming and resistance to sheer.

So far so good, but then again I haven't driven it 2000+ k's yet. I have the proper GL-4 gear oil ready to go in case anything goes wrong with it.

This is interesting me. Is this gear oil choice only important for a particular model of gearbox?

How can I tell what model gearbox I have??

It will be on the vehicle ID plate. I think it is on the D/S firewall. Happy to be corrected if wrong.

I put GL5 in mine when I first got it (+ Nulon PTFE additive). The box was always stiff & clunky when cold,but ok once warmed up. I was later told about the problems GL5 causes in these gearboxes. I changed to the recommended GL4 & the cold change became as good as the previous warmed up change. Much better. I ran the GL5 for a couple of years. I don't believe any significant damage was done, the gearbox has been fine for several years since. Compared to most modern cars it's an old style gearbox anyway without the modern fine tolerances, just the nature of the beast.

Last time I changed the oil I used Penrite Pro 75W85 because a) it's GL4 & b) being full synthetic it flows easier than the equivalent mineral oil which makes putting it in so much easier. Very happy with it. It may be that the less viscous nature of the oil is the reason that I have found a couple of drips of oil (as other 4.2 owners have also reported) at the clutch/gearbox mating. I have kept an eye on this since & found it only occurs under hot & extended 4wd conditions. We are 'on the road' & I bought a couple of (expensive) litre bottles of the Penrite Pro to top up if needed.After driving from Katherine to Cairns via a fair bit of 4wd & slow corrugated routes I only noticed a couple more drips (literally that is all) the gearbox oil level has not noticeably dropped. Just a heads up so you don't need to panic if you find this happening.