lt77 trouble

hi i am trying to rebuild a lt77 gearbox and any help advise would be great as i am starting to struggle i have replaced the main shaft but am having problems with gear selection, the box is on my workbench at ehe moment and would like to be able to select all gears before going to the effort of fitting it, any help would be great many thanks anthony

What are the problems, can you be a bit more specific. Are you rotating the gears while trying to select them?

hi thanks for the reply well its a long story please bare with me, i am building a hybrid and have taken a discovery lt77 gearbox and have fitted a 90 main shaft to it and bell housing, i have been able to rotate the gears so far but once the 5th gear extension housing was fitted i am unable to select any gears and i cant rotate the mainshaft either, i dont really want to sent it away as a exchange unit as it would be nice to fix it myself but i am now having trouble and the landrover workshop manual is not the best when it comes to the gearbox

So its when the 5th extension went on it all went horribly wrong... all I can suggest is that you very carefully look at this, something must just be sticking really good, and 5th gear extension housing is the culprit.

Are two gears engaged at the same time? ie one in the main gearbox and fifth.