Bad sound coming from my 1972

[72Blazerod]

Hi Guys,

I decided to finally put the vette away for the winter, and because today was a nice sunny day I took her out for one last spin. I bought the car in Feb and it has always seemed 'clunk' when I put it into drive (yes it is an automatic). Well while I was taking it out today, it seemed to clunk when I was going around some corners. Not everytime, usually if it was a sharp corner.

Any suggestions as to what it might be? Anyone else had a clunk sound with the Turbo 400? Might I be lucky and just have to tighten something up? Any suggestions would be appreciated.

BTW it is a 1972 coupe with a base 350/200hp engine if that makes a difference. This is my first vette so I am still a rookie at diagnosis.

Thanks,

Rod

 

[JohnZ]

Classic symptoms of "Posi Chatter". Suck all the old diff lube out with a suction gun and replace it with two 4-oz. bottles of GM Posi Additive (P/N 1052358) and two bottles of GM Diff Lube (P/N 1052271) from your Chevy dealer. Put the Additive in first, then add the lube (you'll have some left over). Then drive to a large parking lot and do about ten low-speed "figure-8's" to get the new lube into the Posi clutch plates, and the "chatter" should disappear within a mile or two. Very common problem, $28.00 fix usually works unless the Posi unit is in really bad shape.

 

[GTR1999]

I agree with John too, also check your front differential snubber bushing you may be getting some noise if it has some play in it.

 

[CQRT]

I seem to recall adding "whale oil" or "sperm [whale] oil to quiet posi clutches years ago - - -it struck me as kinda gross not to mention environmentally insensitive - - but it worked!

Do they still market such a product or have the PETA folks prevailed so that synthetics now do the trick ?

regards

 

[Culprit]

...do about ten low-speed "figure-8's" to get the new lube into the Posi clutch plates...

Low-speed... where's the fun in that?

 

[Vettehead Mikey]

I seem to recall adding "whale oil" or "sperm [whale] oil to quiet posi clutches years ago - - -it struck me as kinda gross not to mention environmentally insensitive - - but it worked!

Do they still market such a product or have the PETA folks prevailed so that synthetics now do the trick ?

regards

The real whale oil additive was discontinued many many years ago, long before the PETA extremists were even out of their environmentally insensitive diapers.

GM now sells a synthetic substitute, works just as well if not better than Moby ever did.