Ford Galaxy on tick over rumbling noise from transmisssion dissapears when clutch is dipped no noises at all when driving

You dont say what engine in that year / model . Usually the clutch release bearing doesn't touch the pressure plate / diaphragm till pedal pressed and then can make noise if worn . But under certain circumstances if sticking on shaft or diaphragm faulty , finger/s worn , pressing the pedal can centralise / reposition the bearing and noise goes ( brief synopsis ) . But more often caused by worn gearbox layshaft bearings Check g/box oil level also