You will get a loud rumble from the Trekker if the ash pan door isn't fully closed and sealed by the gasket. Combustion air flows though this area and up through the fire pot to feed air to the pellets. If the door isn't fully pushed in until it "latches" air will cause a rumbling sound. The drawer doesn't really "latch" but there are two friction points on each side that hold the drawer in place. Try removing the ash pan door and sliding it back in until you feel it latch.