Hi guys, am a newbie here and have just bought a golf gt tdi 150 mk4 with 119000 miles on it. When starting from cold a knocking noise can be heard for a couple of minutes and then it disappears. This noise happens weather the clutch is in or out and so im thinking its not the gearbox. The noise has no pattern to it but when it does make a noise, the engine revs change slightly exactly in time with the knock. After 2 minutes the noise completely goes, and the car drives perfectly. Have read all about the issues with the dmf but am unsure if this is the case. Any ideas would be greatly appreciated. Thanks in advance.