Heavy Knock Hot With Torque Applied
^ Broken balancer, pulley hub. Replace parts as necessary.
^ Loose torque converter bolts.
^ Accessory belt too tight nicked. Replace and/or tension to specs as necessary.
^ Exhaust system grounded. Reposition as necessary.
^ Flywheel cracked.
^ Excessive main bearing clearance. Replace as necessary.
^ Excessive rod bearing clearance. Replace as necessary.