I have clicking noise under car around mid section area on my 72CS . It's sporadic and sounds like it mainly makes clicks when coming to a stop as the car downshifts ( vibration) , or accelerating ( under load ) . I put 455 and transmission in a couple years ago and car runs great . The transmission is from speed shop with shift kit ( T350 automatic ) . Needle bearings fell out of u joint in rear when I lowered drive shaft to install transmission . I put them back greased up and didn't replace u-joint 😆 . There's no play in that area of drive shaft I noticed but there's a tiny bit of play in transmission coupling where it connects in front . I don't drive car a lot but has way more HP / torque as I burn rubber down the road with the " one wheel wonder " rear end . I also changed rear end gear oil a few years ago . Could the differential be on it's way out ? Thanks in advance , Bryan

 

Maybe I should of put flywheel cover back on ? I didn't drive in winter or anything but it got wet a few times . Possibly the flywheel is cracked also ?

 

It sounds like you are on track diagnosing. Replace at least the questionable u-joint, but I'd do both while it's apart. Cracked flexplate is possible, as well. Check the trans mount.

 

Could be the rear wheel bearing, they definitely click like that

 

Thanks . I thought it was the rattling metal gas line hitting the frame , but I tied it up to see if the noise stopped and it still makes this noise .

 

I'll have to check that also.

 

Speedometer cable going bad?

 

The speedo needle use to jump around and make noise at the speedometer itself after I installed the transmission but then I wiggled it and placed the cable more relaxed under the car and it stopped doing that . I'm not sure a clicking noise was the perfect description but it sounds like the clicking of metals tapping against each other with the revolution of the rims or driveshaft . Sounds like woody the woodpecker lives under the car 😆 . Not a knock either .... besides it comes and goes inconsistently with it being that . The exhaust manifolds have a few broken bolts and i heard that can make a tapping sound like the engine knocks .

 

I’ve had a loose flex plate bolt make a very disturbing clicking sound.
Good luck!

 

i have a clicking sound like its coming from the transmission when i put it in first second and third gear it sounds worse any help would be appreciated