Hi when i removed the plug there was very little oil left and when i removed the gearbox cover bits of shrapnel fell out and i could see the v shaped part that sits behind main visible gear and slides in and out had snapped off on the left hand side. Is this the end for the gearbox?Hi Tara, it happened to me 3 months ago.As madnoel10 said, the left front wheel has to be removed, the plastic mud guard in the wheel arch too and then you can see the end cover of the gearbox. see 1st pic.
3 bolts to remove to open the gearbox cover. Drain the gearbox first, of course, less messy. And you should see the bolt which holds the fifth gear. see 2nd pic.
In my case the bolt was loose but hadn't dropped. If the teeth of the gear is damage, you need a new one, otherwise remove the bolt, clean and dry it, put some loctite (stud-lock) and tighten with a metric wrench "11", if you don't have the proper socket. Put cover back, make sure that the seal is properly sited in the cover and that's it. Wait for the loctite to set before refilling your gearbox with oil.
I did it in my drive way. just be careful not to put any dirt in the gearbox when it's open.