RE: df-03 makes weird noise when landing???
mate, dont quote me, but I think I know what your trouble is. Check the top cover of your rear diff (or front diff for that matter). On mine, I managed to strip the plastic in the screw holes for the rear diff cover. The torque of the tranny cogs turning was lifting the cover of and hence making a really high pitched grindy squeely sound.
I just put some wood screws in with a bigger diameter than the holes, which fixed it up fine. Had to dremel the screw heads down a bit but yea, it works a treat.