Pulled down my pan to chase a low oil pressure when hot issue. Stock pump with floating pickup tube appears in good shape with no galling. Rod bearings all look good. Main bearings show scoring, so I’m changing them. BUT, the center main thrust bearing has its rear thrust surface worn so thin that it peeled away. There is pressure against the rear of the crank pushing it forward. I’m running a Chevy 4 speed and a hydraulic throw-out bearing What the hell is going on ????