Backhoes are an extremely handy tool but some care needs to be taken when installing one on your Yanmar tractor. The problem is that the yanmar uses the bellhousing as a structural part of the frame. The bellhousing is plenty strong for normal tractor and loader work but add a three point backhoe and you can get into trouble. In order to prevent the tractor from breaking in half you need to be sure the three point has a sub-frame installed. A subframe is a structural brace that connects the front axle support to the rear axle housings. It basically takes the load off of the bellhousing and distributes it safely.