Sunroof rattle

Ive done the usual search but not really found an answer. Most sunroofs seem to rattle during operation or rattle with no movement. My sunroof works perfectly both opening and closing but rattles when completely closed with the switch pressed. Should the operation be a one touch or should the switch be held. I've found pics of the sunroof motor clearly showing the gear. Is that the gear that does the rattling or is there another tucked away somewhere.

Ok, so home now and have just read the owners handbook. Its not a one touch operation its press and hold.

So I press the bottom of the switch and the roof tilts and then slides open as it should. I press the top of the switch and the roof slides forward and then drops into place as it should. As soon as the movement is complete with the roof properly closed if I don't release the switch in time it sounds like machine gun fire, loud machine gun fire.
Any Ideas.

I think there's a limit switch that should shut the motor off when the roof is fully closed. Maybe your roof isn't fully closed, or the limit switch isn't working. Don't hold the switch once it's close as you'll strip the gears. The noise you can hear is the gears slipping. The longer it does it, the worse it will get.