Think this is the earlier g/box with the gear lever on the floor where the later models are cable operated,if it is the earlier one then all I can suggest is to remove the gaiter/sound deadening and the four torx 30 bolts holding the gear lever on and remove it,there is a bearing where it is located into and also a pinch bolt onto the selector shaft and would have a good look at thes and make sure all is in order,have seen gear levers also come apart about half way up but your fault doesn`t sound anything like that,if all is in order then you may be looking for a replacement box,good luck
cdc
April 2012