Grizzly G4003 lathe, loud BANG noise FIXED! The problem WASN'T the Bearings or gears!

Round 2 on the Grizzly G4003 lathe gearbox bang. It's finally fixed, but I totally went the wrong way in figuring out the real problem. It wasn't just the bearings and absolutely was not any shaft and absolutely not the gears... I eventually find the problem and repair it. Can you guess what the problem was? Watch and find out! Music/sounds attributions: Hip hop beats_techno by scale75 -- https://freesound.org/s/323250/ -- License: Attribution 3.0