i think cos its close to the turbo it drys out and goes stiff.its not tioll its off you realise how stiff it is.not sure,but if its a bearing and its dry it will crack when moving.i would check that.its easy to take apart.the tcas should be ok if it passed the mot,they would have checked for play then.also,poly diff mounts cause a lot of vibration on the road and i think the solid mounted beam wont help things vibration wise.