i have a bad gearbox leak (pisin it out), its the rear gearbox seal / rear output seal which ever you prefer

now has anyone changed their seals on the 1200 gearbox or ute gearbox?

can the seal be replaced without removing the gearbox?

If it's the seal and the very end of the gearbox where the tailshaft goes in, it's the rear extension housing seal (i think that's how it's termed). Know i haven't done one on a A-series (only on my L-series dattos) but they are easy in general. Drain oil out of gearbox, remove tail shaft (mark it before you remove it), now in the housing you should the seal a thin black ring looking thingy (L-series are about half a centimetre in diameter the ring in mean). Now since this seal is stuffed you can lever this out with a screw driver. Now have a look at the seal is it torn or split and this is why it leaked oil? Or have a look at your tailshaft is the input(?) scorched or discoloured. I ask this because there are two possibilites with this. 1 The seal is broken and that's how it leaked or 2. The tailshaft has pitted and worn a groove into the surface and the oil seeped past the seal.
Now if the seal is damaged, clean and that it to the parts place and get a new one (approx $20). If its the tailshaft either speedy selve it or get another one from the wreckers.
Replacing the seal grease it (supplied) and replace (can be pushed in by hand) and refit tailshaft. Also REMEMBER to refill your gearbox. Oh yeah you don't have to remove the gearbox to do this