Would a front diff?

My front end noise came back. Ugh. When I bounce the car from the fenders above wheel wells I can hear the noise. It�s a clear knock. Either side. Can�t tell which side is louder. Would a front differential do that. When I�m driving there is no whining. I get this knock at low speed. Like under 5-10 mph. 02 C4S Thanks.

Is the knock speed dependent? i.e. is it cyclic and varies with speed? If it happens when parked and only by pushing down, it seems unlikely to me that it's the diff. More likely the front sway bar or end links are loose somewhere.

Happens only on bumps and sometimes on launch (starting to roll). I only hear when going very slow. Probably happening at speed but can�t hear it. It�s strange. Usually happens after I�ve driven the car, then I get back in and start driving again or when I take a hard left turn into my driveway and continue up my short driveway. I check mounts torque, fine. I replaced drop link on left side before and recently checked sway bar torque. Timing was great, had a couple guys coming to look at to buy.

Worn CV joints?

If you can cause the sound by bouncing the front end when the car is stationary, I would look at sway bar, strut and suspension arms as sources rather than any of the rotating stuff. I guess the diff has rubber mounts? Could be those too.

Is there any way to test these parts or just replace and hope for the best? Thanks.

Find a good Porsche mechanic and get it properly diagnosed. Much cheaper than throwing parts at it blindly.

Okay, thanks I will do that. New Porsche mechanic in town I hear. thanks everyone.

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Put the car on a lift or stands, use a prybar (gently) in/around the entire front-end and suspension and see what's loose. Some link or ball-joint will move in a way that it shouldn't. Having a mechanic do that is also a good option. EDIT: By gentle, you may have to apply some force, they are meant to handle the weight of the car. I just mean the areas and pressure are selective and not jerky or random.

When did it first start? Had anything been done? What happens if you jack the front up? Try both sides. When you say it happens on a hard left it could be that the control arms have been torqued up without the car being on the ground. Jack it up and see it you hear a cracking/clicking sound. Otherwise as said, get it up in the air and go round with a bar and look for slight movement in every joint.

I chased a sound like that to worn control arm bushings, sounded like metal to metal clunk over small bumps at low speed.

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Same here. I had exactly the same "clonk" at low speed / change of weight of the car and it disappeared changing lower the control arms

Indie went over front suspension and diff, he believes everything is fine. He thinks the noise is the h&r springs moving just enough in Bilstein strut perch to make an occasional knock. Said non issue other than occasional knock. I�m calling it case closed. Thanks All.

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I don't think that a properly installed shock should touch the spring at any moment or condition and cause any knock. It is really difficult to identify a bad control arm bushing without removing it. How did your shop assessed that they were ok?

If it�s the spring causing the clunk it�s because the top bearing isn�t operating/turning properly (ie. It�s binding) or it isn�t there (it should be but it possible that whoever changed the springs & struts didn�t replace them). Clean and re-grease or replace the top bearing(s) - I would do both sides.

I could but it is so intermittent, I�m l leaving alone. First, I don�t feel like doing it and second, it would cost I guess 1k to do. If it becomes more frequent, I�ll fix.

Of course, you�re going to do what you please� I seriously don�t think it�ll cost you $1k though. I think the bearings are around $60 ea. (there are 2 one right one left). You could diy it in a few hours. I would think a shop with suspension experience could do it in 2 hrs. ($400 labor). *it�s probably a potential safety issue if the springs are binding at the top mounts.

Just drove home, like normal; not event. I did ask if safe and his reply was yes. I�ll keep my ears open and if it comes back and gets more frequent, I�ll address. Thanks. FYI, I could not get that job done for under 1k here. Labor is ridiculously high here. I�ve been trying to move for years. 😀

The guy who did was a pretty seasoned European auto mechanic. He�s actually the owner so I would hope he did it right. These were replaced. Not sure if from back or front. Would being a C4S make fixing more difficult. I was able to do on Boxster 986 relatively fast. This seems more involved because of all the awd stuff. Thanks for the help, I do appreciate it.

^^^Yup, those are the strut top bearings. If they�re there they shouldn�t be binding. I can tell you though that it does happen. I had Bilstein B8�s with H&R sport springs on my car for a few years and it did the same thing a few times�*they�re only on the fronts�

That�s the thing, it not always. It�s just every so often it starts knocking and keeps going until I park and wait a few hours. Always after I�ve been driving for a while (20 mins or so) but as mentioned, not always and not often. What do those parts do? What�s actually moving? Without actually doing one, I�m having a tough time thinking what this part does.

It allows the top spring perch to rotate as the wheels turn (due to the geometry of the front suspension).

DPorto, did you just live the noise or swap out? curious if as easy to swap out the front struts on a C4S as on my 986. I�m thinking it�s the opposite. The front was super easy and the rear was a biatch.