New here and hoping someone can maybe shed some light on this rattle for me.
2014 3.0tdi with S-Tronic gearbox.
For the past 20 months (and 17k miles) my car has an audible rattle which is present when allowing the car to creep forwards or backwards. This rattle is ONLY present when the idle speed has settled to 600rpm. If the idle speed is higher than that due to it being cold or doing a DPF regen the rattle is not present and engine sounds much smoother overall.
With the engine idling at 600rpm you'll can feel slight vibrations through the car as well as an audible, but very slight rattle. If I push the throttle slightly to increase rpms to about 675rpm, it's buttery smooth and no rattle noises.
Sometimes you can also hear a rattle very briefly on gear changes when attempting to accelerate moderately in D mode and it upshifts earlier than you'd expect it to.
I've had the flywheel changed, a brand new gearbox and the tensioner and auxiliary belt changed but the noise is still there and no different to what it's always been.
I have noticed that if I turn on the AC the engine sounds much smoother and the rattle is practically gone when creeping forwards or backwards (possibly due to the extra load on the engine?).
I'm at a loss as to what it is because the car appears to drive absolutely fine but this vibration / rattle when idling and crawling ruins what is otherwise a smooth car.
Any ideas as to what this could be? I'm thinking either the clutch packs (they weren't changed when new gearbox and flywheel were fitted) or the Aircon compressor (due to this having a direct impact on the noise based on it being on/off).
Video I took a while ago showing the noise when creeping. This was before the gearbox and flywheel were replaced but the noise is no different now.
Sorry for the wall of text and any help is appreciated. Thanks