I believe all the air filter brackets break on these tractor. I had some scrap metal and shaped it to brace it a little better. Might say I added some beef to it and it's held up since. As far a diff lock you have to hold it down while using it the minute you let up it disengages. Very good little tractors that can do lots. I got mine about six years ago used and it had little over 3'hundred hours and haven't been disappointed with it yet. Installed several hundred feet of water line, sewer lines, driveways, clearing, tilling, mowing, bushing hogging, moving dirt. And the list goes on and on. May not be the fastest in the world but handy as can be.