Shake on acceleration

My diesel is starting to rumble/knock on acceleration, especially in 4th and 5th gears. The rumble disappears completely when no acceleration is applied and is definitely not coming from the engine bay but underneath. The car has done 150k and is fine in all other respects but I don't want to go through the hassle of getting a new gearbox if that is what is needed. Any ideas/help appreciated. Thanks.

from the last news http://ift.tt/VU3MNs

via IFTTT