check out the needle roller bearing below the oil seal where the selector shaft goes down into the g/box,bad for seizing,you have to disconnect the cables,reverse switch connector and the ring of 10mm bolts holding the selector lid on,try and get some penetrating oil onto the bearing to get it moving,then grease it up when moving,if it is too far gone you can`t get the bearing separate now and have to take the whole housing but a scrappy may help you out for that
cdc, February 2012