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95 C4 Driveshaft Slop?

T

tvalley641

Guest
15k miles; auto; babied. She's (or is it HE) my first one. I'm not worthy! Bought her last August.

From day 1 I've noticed a funny clunk-type noise (not so severe) from the rear each time I slightly give her a little throttle coming out of the corner. Typically, I've slowed down to about 15 - 20 mph when this happens. I hear this (and kind of feel it) with either right or left-hand turns. It reminds me of the clunk I used to get when shifting my '86 Monte Carlo SS from Park, through Neutral to Drive, while standing still. I was told that was a little drive-shaft play and not to worry about it. It never got better or worse over 160K mi.

I can reproduce the noise if I hit the throttle, and then let up, and then hit her again (all at no more than 15 - 25 mph). The slight clunk appears immediately after I give her throttle after letting off a bit. If I'm over 25 mph, or so, I can give it all the "goosing" I can without the noise. Also, if I floor it off the line.....no noise!

Do any of you boy or girl racers out there have any ideas?

Ted Valley
Dayton, Ohio
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
It's a how bad question

If it's a TIC it could be the splines from the rear end hub bearing.

More of a kunk,.U joints or splines on the tail shaft.

A Kla-unk rear end.

but a 95 with 15K

How was it stored? Do you know it's history?

Need more

Mike
 
T

TomsToy

Guest
Clunk

Assuming the noise is comming from the rear axle, I would be suspect of a worn differential shadt, pinion bearing, or washer. That would let the ring & pinion gears have larger clearance and could cause a clunk on acceleration or deceleration. Also look over the rear suspension to see if anything is loose.
Lots of Luck
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Like all things

A diagnosis over the internet is tough at best.

It could be a bad shock.

The more info you give us... the better we can
guess!

Mike
 
T

tvalley641

Guest
Thanks VigMan and TomsToy -

How might I isolate that light CLUNK without ripping her all apart?
It is definitely coming from the rear. I forgot to mention, at speed all I hear are those hard tires.

Any test techniques that can key in on the suspect part?

Ted
 
T

tvalley641

Guest
I thought of jacking 'er butt off the ground and trying to rock the tires back and forth, quickly, to see if I can detect play in the shaft.... or might I get play with any C4 auto by doing that?

Ted
 
T

TomsToy

Guest
clunk

Well, if you jack one rear off the ground and rock the wheel back-and-forth you may be able to detect the location of the clunk noise. Don't forget to check the suspension. I had a similar noise appear and it turned out to be the top shock mount was loose. If the noise is from the rear axle, you'll need to get a dial indicator to check backlash. All my analysis charts indicate a worn diff shaft in the case. If the shifting from right to left changes the tone, I would suspect a rear wheel bearing.
Good Luck
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
WILD thought

IF this pilot was maintinance obsessed
AND
He had the rear end fluid changed
BUT DIDN"T
use the correct GM posi lube.

It could be the clutch packs slippin

Do you have the maint records?

Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
AND

I'm having a tough time @15k thinking U joints & rear wheel bearings.

But anything's possible

Mike
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
But if your going to Jack it up anyway

Repost rear bearing test.....


As far as the rear end

Get the car in the air.... grab the rear wheels @ 12 & 6 O'clock

and rock
Top away from you
bottom towards you
then reverse.

This will tell you your bearing runout if you have more that 1/4 inch.. that's bad.

If your unsure, try the fronts.. hopefully their tighter.. to give you the correct "feel".

Check closely the 1/2 shaft u joints.

Mine looked ok visually but applying the E brake and putting the car in rev & drive showed some BIG play in the U joints.

I'll bet your right side rear is worse then the left.
 
T

tvalley641

Guest
Mike,

Reviewed his maint. records. He was smart enough not to have changed diff. fluid.

Only things I found out of ordinary was R/R tire repaired and replacement of rear lighting harness (He stored the car in a barn the last 6 mos. he had it and mice ate the rear wiring). I don't think those little buggers have teeth strong enough to do the number on diffs...... do they?!.:s

Ted
 
T

TomsToy

Guest
vigman's advice is right. I'd check everything out in the air and seriously consider changing the fluid.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Ohhhhhhhh they got BIG SHARP TEETH!

Not ther rear end directly.......
( unless it was covered in a nice shallot sauce)

IN A BARN?!!!!!

( This is getting better by the minute )

Have you had the car in the air yet?


I smelling a RAT..( well not a very big one.. he disguises himself as a mouse often times.)


The rear wiring loom is jacketed... now I know what mice are capible of ( they chewed thru a few wiring harnesses @ work)

\
Mike
 
T

tvalley641

Guest
This weekend I'll take a look at her (er...it's) rearend and check all the things you guys suggest. I'll let you know what I find. I'll learn her good sooner or later!

Thanks
 

Full Bull

Well-known member
Joined
Dec 7, 2001
Messages
185
Location
San Antonio, TX
tvalley...guess what? I started getting that same clunking noise in the rearend of my 95 coupe this past weekend...whilst i was doing some heavy stop and go's in Austin. It clunks when i give some gas, back off and then accelerate....around 15-20 mph. Sounds like tranny to me...but, then I'm neither a mechanic or very mechanically inclined. But I do know that the car has never been kept in a barn...so the chances of it being a mouse or rat are very miniscule!! Let me know what you find....might very well be the very thing causing my clunking....
 

Mad-Mic

Gone but not forgotten
Joined
Feb 12, 2002
Messages
1,853
Location
Annapolis Maryland
Corvette
1987 Redskin Red Coupe
hey i got the same thing!

i just purchased a 87 vette with auto trans. i had this problem before in my 82 Z/28 and it was the trans mount i busted. i'm gonna put mine on the lift as soon as i can and give it a visual. it's not bad i just hear it / feel it once in a blue moon. i'll keep you guys posted.
 
T

tvalley641

Guest
Hey Newbie!

Wow! Another one with the same problem. Tell you what, why don't you let me know what you find? That way, I'll not have so much troubleshooting work to do. ;-)

I'll give you a ring when I find out.

Ted
 

Full Bull

Well-known member
Joined
Dec 7, 2001
Messages
185
Location
San Antonio, TX
I've got this posted on at a couple of other sites...will let you know if there's someone out there who's already got it figured out.
 

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