Drive Train Clunking

rrs1Member

I have a clunking noise that is coming from either the ZF or the drive shafts. It happens on acceleration either from a standing start, or if coasting and then getting back on the gas. It's as if some slack is being taken up before the drive is actually put to the ground, so it's kind of a slapping/clunking sound.

It also happens to a lesser extent upon deceleration.

With the wheels off the ground, and turning one wheel back and forth I notice there is quite a bit of play/slop, maybe 1/2" before the axle flange turns. I know there is some play, but how much?

The transmission shifts fine. Is there something else that can happen inside a ZF besides shifting problems that would cause this noise?

Is there a way to know or test if the drive axles could be causing this besides looking for the "ring of death" snap rings turning into the metal? I don't know if it applies on a Pantera, but it feels like U joints are worn.

Thanks for any insight.

6/7/166:34 PM

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jtpanteraMember

I agree that it is your u-joints in the halfshafts. Not that hard to inspect if you jack up the rear of the car and methodically rotate the shafts while checking the joints.

6/7/167:33 PM

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rockyMember

Just saw an ad in the POCA Newsletter (Pantera Parts Connection, Carson City) for U-Joints at $36 each. Or you can get the halfshafts complete at $300 each (with exchange).

Might be worth looking into after you check your U-Joints.

Rocky

PS - I just saw the ad, not sure if there are other deals out there.....

6/8/164:44 AM

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rrs1Member

Okay, thanks will take the axles off.

6/8/169:06 AM

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rickMember

I was lucky. My ujoint failed pulling slowly away from a stop sign. That was still sufficient to bend a passenger rear shock when it broke. I wasn't even aware that mine were bad.

Never run with loose/worn ujoints.

6/8/1611:16 AM

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rrs1Member

So you didn't hear any noises or feel vibrations beforehand? That's what is odd. Nobody has described the type of noise before failure I'm getting either.

6/8/1611:21 AM

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rickMember

Nope. It's not like my car was real smooth and quiet to begin with. ;-) Easiest way to check is with the wheels off the ground and turn it by hand back and forth. So how often do most people (like me) do it... Almost never unfortunately and since they last for years it tends to sneak up and bite you!

6/8/161:59 PM

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rrs1Member

Well rats it is not my U joints or axles they are solid, clean and no play anywhere.

6/8/165:51 PM

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jfb05177Member

a WAG, how about the ZF or engine mounts

6/8/165:57 PM

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rrs1Member

I have checked those several times hoping, no luck. Now back to suspecting the excessive play when turning the mounting flange on the ZF. I can recreate the noise with a swift twist as the slack is taken up.

6/8/167:07 PM

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tsoloMember

Have you tried changing the gear lube and ensuring that the box is full and not low on level?

Steve

6/9/163:14 PM

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rrs1Member

Yes sir.

6/9/165:38 PM

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jfb05177Member

I am just thinking here...
If you put it in gear, lift one wheel, then measure accurately the amount of wheel roation back and forth while in each gear.

I would assume their would be a known backlash that could be interpolated to wheel rotation.

6/9/166:16 PM

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forestgMember

Probably something in the limited slip setup. Give Lloyd a call at RTB.

6/10/167:26 AM

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rrs1Member

LOL at RTB. But I think you are correct.

6/10/1610:40 AM

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rockyMember

There's a lot of things going on in there, that might be making noises....

There's only a few things you can get to without pulling the box out.

I agree with at least doing the check JFB mentioned. At least find out if its the same on both sides.

If this is really correct, and you mean the Axle flange on the side of the box, I would be very surprised... I thought that the connection between the wheel and the Axle was very solid.

With the wheels off the ground, and turning one wheel back and forth I notice there is quite a bit of play/slop, maybe 1/2" before the axle flange turns...

That would say it's in the connection inside the bearing carrier.

See this picture - I think if you can turn the wheel without any motion on the driveshaft - you have a problem between part #7 & #16......

Wilkenson Catalog

6/10/163:17 PM

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jfb05177Member

good thinking
like you stated the the nut 18 is loose and the splines are worn on 7/16

or maybe the bearings 10/15 are loose in the upright 13

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6/10/163:38 PM

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bosswrenchMember

Just a thought- I've seen one Pantera- used for drag racing with a highly modified engine- that twisted the sliding splines inside both halfshafts. In this car, the sliding length-adjuster splines were sloppy-loose from the dumping of the clutch, along with apparently not ever being greased, as the factory zerks were missing.

6/10/166:33 PM

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rrs1Member

Thanks guys appreciate the thoughts. I have a couple more things to check first, but I don't suppose much could be done with the side cover off while still in the car?

6/11/165:35 AM

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jfb05177Member

if you have the wheel rotate 1/2" on the tires outer diameter, the ZF flange rotation expected would only be ~0.07" on its outer diameter with no lost motion in the half shaft

EDIT;
SORRY I forgot about

quote:
Originally posted by RRS1:...when turning the mounting flange on the ZF. I can recreate the noise with a swift twist as the slack is taken up.

I was still thinking

quote:
Originally posted by RRS1:
With the wheels off the ground, and turning one wheel back and forth I notice there is quite a bit of play/slop, maybe 1/2" before the axle flange turns..

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6/11/166:08 AM

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