when i start up my disco i get a loud rattling sound which usually stops after a few seconds and also does it at switch off,i spoke to a friend of mine who says it may well be just a clutch spring which has broken and is rattling and is nothing to worry about.Any ideas guys plz

 

It most likely will be one or both of your cats rattling. Crawl under the truck and use a rubber hammer or something to hit the cats, if they rattle thne you need to do two things, find out why they have failed, repair tthat issue and then rplace the cats or Y pipe assembly. Is your check engine light on?
Mike