what causes loud clunk/bang/jerk in drivetrain when I put C6 into gear?

[mycoses]

1971 mach-1 351C rebuilt C6 When I put the C6 into gear there is a very loud metallic clunk/bang noise and jerk in the drivetrain which is very irritating and does not sound or feel normal.The drivetrain engages with a very loud clunk. What could be the problem.

 

[PoppyMod]

1971 mach-1 351C rebuilt C6 When I put the C6 into gear there is a very loud metallic clunk/bang noise and jerk in the drivetrain which is very irritating and does not sound or feel normal.The drivetrain engages with a very loud clunk. What could be the problem.

Hi
Two thoughts come to mind.
1. The universals have play
2. Excessive play/lash in the ring and pinion
It only takes a a small bit of play to reverberate. If it's a lower sounding "clunk", then, most likely it's the rear.

Good Luck!

 

[CarMichael Angelo]

I agree w/ Poppy. That or U joints are probably causing the noise.

 

[rbohm]

usually the front U joint is the problem.

 

[v8only]

check your idle speed too....a clunk followed by a big jerk may mean you're idling too fast.