Hi, i too lost all my gears due to a selector problem. The problem was that the small bolt that secures the selector shaft to the selector mechanisum had come loose and fallen out. If this is the problem it is possible to remove the selector from above and replace the bolt (you need to remove various bits and pieses and drop dowm gearbox end), however this will leave the bolt in the box which will probably cause big probs. i ended up taking box out and splitting to get bolt out. lots of work but low cost! Good luck