I have a Clunk,Knock,Pop type of sound coming from somewhere in the rear of my 72 cutlass.The entire front suspention is new and has been checked and is tight when pulling and pushing on things.My mechanic said that it's coming from the rear underside of the car.....About a month ago I got an front end alignment and everyyhing was and still is great on the alignment.I myself pulled the drive shaft twice to fix my transmission speedo drive and driven gear.I put the driveshaft back in how it came out...never messed with anything except torquing the u joints back down......My car has a pretty built motor and has always kind of violently went into gear when I put it in drive or reverse.I just make sure I brake hard.......It mostly makes the knock/pop/clunk type sound when I make left and right turns and braking....but sometimes it makes the sound when I put the car in drive or reverse....and it violently goes into drive or reverse.I cannot reproduce the sound pushing the car up and down from either corner.....I did not see any broken springs or shock mounts.....Im suspecting the u joint or rear end differential internals...because I never knew u joints to cause a single clunk going around a corner.Oh and also my rear end is a full time posi 4:11.....Any help would be appreciated....My mechanic said today that he thinks its the u joints because of how aggressive it goes into drive and reverse....Any thoughts guys!🤔🤔🤔 and no my drive shaft doesnt shake or wobble on the hyw....neither does the sound happen when Im driving strait. Only when I go around corners or when I put car in drive or reverse.....Also front and rear wheel bearings have been checked.Thx!

 

Check the rear brakes on both sides for loose parts if it's drum brakes first then If that's not it you may have to look inside the differential. Let us know what you find.

 

Will check tomorrow asap and report back!Thanks! I cant see my transmission mount either.....I may have to see if I can pull it and see if its gone bad.......as well....and I promise I will report back what it is when I find this out so as to help anybody else that experiences these same symptoms.

 

The fact that you hear it more on turns is leading me towards the spider gears in the diff.

 

Definitely check all the external possibilities first. I had some noises on a car once that turned out to be loose bolts that hold the transmission to the motor.

Trans mount is a real possibility.
Check tunnel above driveshaft for evidence of driveshaft hitting it.
Rear control arm bushings bad?
Sway bar loose and shifting?

 

Have you added rear end oil in a large quantity lately?

 

No ,I actually only started driving the car about 2 months ago.....I have never even checked it......I'm going to check it today when I get home from work....asap....Should of done it yesterday but my body fell to sleep......lol.

 

Is your rear end a posi or has it been modified and had a spool installed?

 

Hmmmm....Don't know about spooled,but it is a posi.......full time posi.....no slip......both tires are always engaged.....

 

If its a spool, which will act as you describe and sucks on the street, then that noise will not go away. If its a posi, there an additive that goes in to prevent the clutches from chattering during turns.

 

Hmmmm.interesting none the less....I only think the sound is out of place because for about the first month and a half driving it......it never did that....hmmmmm