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

[svocamper]

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.

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.