Flywheel Noises
Loose or cracked flywheelA loose or cracked flywheel will produce an irregular thud or click. To test for a loose or cracked flywheel, operate the vehicle at approximately 20 mph (32 km/h) and shut off the engine. if a thud is heard, the flywheel may be loose or damaged. This type of thud is loudest on deceleration.
Torque converter-to-flywheel or flywheel-to-crankshaft
Loose torque converter-to-flywheel or flywheel-to-crankshaft bolts will sound similar to bearing knock. This condition produces several raps during quick acceleration on a free running engine. Depending on the idle smoothness, when the transmission is in gear, the noise may or may not appear. Check the torque converter-to-flywheel and flywheel-to-crankshaft bolts before attempting to Investigate any bearing-related knock.
NOTE: Be sure the converter-to-flywheel bolts are not too long. Converter bolts that are too long may dimple the torque converter clutch apply surface causing a shudder condition.