I have alot of trouble with this but I found this out it s strange was. This is when the tray goes foward about a cm and then stops
1. Take of the metal part of the disktray that says " Xbox360" on it. It should come off without too much effort.
2.Turn the xbox so it is flat on the ground ( disk tray above plugs), and make sure you can see inside the 360 from the space you made from taking the metal part off.
3.look hard,in the space you should see a little white piece of plastic. Look harder, next to that you should see two metal gears.
See whats is hapening if your tray just goes clunk and stops dead is that it is hitting the gearsmstoping thetray completely.
4.Get a small metalobject ( movable part of nail clipper is what I use, a small siscorwould do too, it just has to be small,long and flat).
5. Press the button and imedietly after slide the smooth flat metal object between the gears and the disk trey. You can press down alittle if you want. From here it should just keep on moving until it is out
Well thats it, mydisk tray always jams, and this always works.