[Warning this may be disturbing to fellow micra owners]
2nd gear decided to give up and lose the vast majority of its teeth, there are a few, maybe 6 or so left - but even those ones are still damaged.
I was driving along pretty slowly, and I noticed that whenever I was in 2nd gear, I heard this constant ticking noise "tick tick tick" etc. It didn't do it in any other gear at all. After trying to rule out various rattles I thought to myself (famous last words)..
"I'm sure its only 2nd gear, so stuff it, I'll boost it in 2nd and see if it still works"
So I proceeded to boost 2nd gear, it made probably 5psi just starting to spool up and BAM crunch shudder crunch etc. Game over. Luckily I could just crunch and roll down the hill a bit further to my mate's place where I proceeded to park the vehicle and go inside to crack open a beer and begin the night's festivities forgetting about my broken car.
I spent Monday the public holiday "Labour day" (how appropriate) labouring away removing the gearbox, taking photos and playing with it. Learnt a lot from doing that, had never had to do it before, so that was fun. Pretty easy really, a couple of minor things like the right hand CV joint being a bitch to remove, but quickly removing the suspension arm and yanking the whole lot out soon fixed that. Apart from that it was all pretty much very simple nut and bolt removal and yanking the right things in the right order, you can't go too far wrong on the removal.
The first confirmation sign of my hypothesis was removing the oil drain plug before removing the gearbox. The drain plug is conveniently magnetic so that it holds onto any lose fragments of metal you might have floating around in your gearbox oil. When I removed the drain plug, it had about 4 gearbox teeth stuck to it hahahaha as well as about 10 million other tiny metal filings.
Once inside the gearbox I discovered heaps of crunched up metal, shavings, snapped off teeth and general schrapnel all over the place. Because of the few remaining bent teeth and the metal flying around inside the gearbox, it would intermittently lock up regardless of what gear you were in after this happened, this deemed the car undrivable and completely dangerous!
Its now time to get stuck into the research and talking to everyone to find the perfect solution. Ideally I want to steer away from all things "dog box". A mate of a mate in Queensland has lots of experience destroying ET pulsar gearboxes, so he has some good knowledge we can call on to get his thoughts aswell.. He's played around changing cogs and doing this and that with them, and we also seem to think that the gearboxes might be the same or very close between the ET and the micra.