I have a recently acquired M1078 that has developed a starter issue that is proving to be hard to nail down. Truck ran and drove great for a couple months. Went out last week to take it out for some exercise and I could hear the starter motor turning, but the engine would spin. Removed the starter thinking the bendix had failed and took to a local starter/alternator shop, who disassembled, cleaned, and check it over and found no problems. They bench tested and it worked perfectly. Reinstalled the starter and same issue. Starter spins, but not engaging the engine. BTW, the flywheel teeth that are visible look fine and no noise that you would typically hear when teeth are damaged or mot meshing properly. So the starter was removed for a second time and taken to a second starter shop who bench tested again and found no issues. He suggested that the ring gear on the flywheel may be slipping. Have any of you ever encountered a similar issue?