Update...Found #1 Piston con rod bearing as the culprit. Removed all spark plugs and rotated all pistons to TDC. Inserted a screwdriver in each spark plug holes and rotated each piston just past TDC and felt #1 drop. This procedure indicated that I have a bad rod bearing ☹️ Tomorrow I’ll drop the oil pan and inspect the damage. What sucks! I recently installed a rebuilt tranny. Now, I’ll have to rebuilt the engine. Can’t complain, it’s pushing almost 300k
