2002 Boxster S - Clunking after releasing the clutch / shifting

[cky3k]

Hi All,

 

I have a 2002 Boxster S with 91k on it.  I just purchased it within the last 8 months and I've slowly been trying to tackle all the issues.  It is the 3rd one that I have owned, and I actually have a 4th one right now too (its an 03 base).

 

The problem I am having is that there is a clunking after I shift at low rpms (3000 range).  It is a very obvious clunk and it is very unsettling.  I had the motor mounts and transmission mounts replaced (3 total mounts), but the problem is still there.  It is also particularly noticeable when I shift at 2500 or so and dont get right on the gas.  Giving it gas minimizes the clunk.  I thought for sure this is motor/transmission mounts, and so did the mechanic.  But now the problem still persists.  I just drove the 2003 base and there isnt even the slightest hint of an issue like this.  The car with the problem has 91k (02 S).  The 03 base has 110k.

 

Any thoughts on what this could be, or what my next steps should be?

 

Many Thanks!

[JFP in PA]

Check the axle CV joints for excessive play.

[txhokie4life]

What JFP said -- also make sure the CV Axle bolts are tightened (check torque specs).

 

Edited August 9, 2016 by txhokie4life

[Hilux2400]

I assume the wheel bolts are tight? 

[staffy]

i had somthing like this happen to me, turned out to be the long suspension arms that go from the coffin arm to the chassis behind the seat

[cky3k]

Thanks guys,  The 3rd mechanic is now stumped.  He is suggesting to my warranty company that we replace both axles (as one does have some play).  Mechanic 1 said that it was the rear track arms.  Mechanic 2 said the track arms are fine and did all 3 motor/tranny mounts. Mechanic 3 is saying axles MIGHT be it, but is really stumped.

 

It also seems to be most obvious if you just "dump" the clutch at lower rpms, by releasing the clutch and not getting right on the gas.  What I am describing is not as abusive as it sounds, and its totally cool on my other boxster and my gti.  The clutch is pretty responsive (especially compared to other boxsters, but I do wonder if it could have something to do with how well it meshes.  My last 03 S, when I put a new clutch in and resurfaced the flywheel (I know youre not supposed to/cant but we did), when I'd slowly back out of my spot, I could hear/feel it wasnt perfect.  Im not saying these are the same at all, but it makes me wonder if you guys have any experience with a not so perfect clutch situation causing other issues.  (For example, I know what a broken throwout bearing feels like- and thats a good example of a broken item in the cutch that allows the car to work, but shows other symptoms.)

 

 

[JFP in PA]

A perfect clutch is just that, perfect and without noises or vibrations.  I am beginning to wonder if you may have a dual mass flywheel on the way out........

[cky3k]

That could be very likely.  The car has 90k, is on its second clutch from 60k, and its original flywheel.  I actually have a warranty on the car (good for another 8 months- previous owner bought from carmax).  I wonder if the flywheel would be covered under warranty... The clutch definitely wouldnt.

 

Does anyone have any troubleshooting tips for identifying a bad flywheel?

 

Any other input on the flywheel idea?  Recommended reading etc?

[JFP in PA]

12 hours ago, cky3k said:

That could be very likely.  The car has 90k, is on its second clutch from 60k, and its original flywheel.  I actually have a warranty on the car (good for another 8 months- previous owner bought from carmax).  I wonder if the flywheel would be covered under warranty... The clutch definitely wouldnt.

 

Does anyone have any troubleshooting tips for identifying a bad flywheel?

 

Any other input on the flywheel idea?  Recommended reading etc?

 

There is a simple twist test that the flywheel needs to pass to be consider OK to reinstall.  If it fails this test, it cannot be repaired, it must be replaced.

 

As for replacements, stay with the dual mass design, it is the only torsional and harmonic dampening device in the rotating mass, changing it for a single mass unit can result in noise, poor drivability, and ultimately to fatal engine damage, regardless of what your read online.

[grmccloskey]

I have the same issue on my 2001 986, 88k miles.  Did the clutch at about 78k.  DMF was checked and met the inspection spec.    It seems to be only in first and second when letting the clutch out fast.  Checked CV joints, they were good but changed them anyway and it did not go away.  Power bled the clutch three times, still there.  Checked trans and engine mounts, seem to be solid.  As long as I baby the clutch there is no bump.  If I drive it like I stole it, bumps or clunks hard enough to hear and feel it.  My best guess is that the DMF is now sloppy?

[JFP in PA]

I would go back again and really look closely at the front engine mount, and both CV joints.  These are common sources of your complaint.

[grmccloskey]

JFP- I already thoroughly cleaned, inspected, relubed, and re-booted the CV's.  All four were in perfect shape.  I flushed all the grease using a parts wash tank pump with solvent into a fine white cloth and saw no metal shavings or rough spots.  I replaced the inners anyway.    Will reexamine the front engine mounts.  Thank you.

[grmccloskey]

JFP- I already thoroughly cleaned, inspected, relubed, and re-booted the CV's.  All four were in perfect shape.  I flushed all the grease using a parts wash tank pump with solvent into a fine white cloth and saw no metal shavings or rough spots.  I replaced the inners anyway.    Will reexamine the front engine mounts.  Thank you.

[grmccloskey]

JFP - you nailed it!  I was skeptical but followed your suggestion. The front engine mount was trashed.  Replaced it and the clunk is gone.  It runs a lot smoother and quiet in all gears and speeds now.  Thanks man!  One heck of a lot easier and cheaper than a new DMF!

Edited January 10, 2017 by grmccloskey

[JFP in PA]

Glad you got it sorted.  The front  mount is a common source of the problem you were having and always one of the first things we look at.