series 3 gearbox probs

Hi went out today to lr show at eastnor castle and think I broke 2nd gear was going up incline in 2nd while turning and it locked up hi/lo lever stuck and no go forward or back got towed out the way and it seemed to free everythink up but now 2nd just grinds but sometimes if I,m lucky it goes in and drives but its not happy and has been iffy for a while jumped out only in 2nd a few times
how easy are these to rebuild or has anybody idea,s as to where i may find another gearbox and is an overdrive worth looking at fittingat the same time its on a 71 series 3 any suggestions welcome cheers all in advance

Do a search on this site, a sS2/3 gearbox is real easy to do, you still need to be handy.

I have a couple of series 2 boxes for sale...where are you?

changing the gearbox is easy, getting the rusty bolts out of the seatbox is the tricky bit.....the last time i did one was extra fast as I needed a gearbox cross as well