Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Hello.I'll try to answer your questions by starting at the top of the list. .1. A grinding noise wouldn't be a noise associated with an auger gear box failure. If the auger is turning without skipping or stalling when engaged the box is probably not the issue. The grinding noise is likely the impeller contacting the housing. This is an indication of an impeller shaft bearing failure. 2. If the gear box is at fault, the quickest way to fix the machine is to replace it. I've rebuilt these boxes before but only if they were bolted together not riveted; and then only because a replacement wasn't available.3.A used one may work, but it may have the same flaws.4. Here is the answer that will be of the most value to you. Regardless of what the problem is, you'll have to disassemble the auger/impeller housing from the rest of the machine . The housing is held to the rear or engine/drive half of the machine with several bolts on either side. Remove theses as well as removing the drive belts on top from the top pulleys. After this you'll end up with two halves of the thrower, the auger housing and the engine and drive half.On the auger housing, remove the bolts on the outside of either end of the auger. On the back, remove the impeller drive pulley. You should then be able to pull the impeller and auger out of the housing. Here I think you'll notice the bearing that the impeller shaft spins on. This I feel is the origin of the grinding noise. When this fails, it no longer supports the impeller shaft and lets the impeller move from center when engaged, and contact the housing. If so, it needs to be replaced.5. If gears are available, sure, usually the whole box is the replacement part. There are parts diagrams and exploded views in the owner's manual if you have one, if not I include the web address for MTD. I hope this helps. Curtis http://mtdlawnmowerparts.com/manuals.php