first thought that comes to mind is pad shift.

As far as rust buildup goes, surely it would take more time to bind to where a sound could be heard from it breaking lose? Just a thought.

Best of luck, chasing down sounds its never fun. Been there, dont that on my Evo. Under acceleration and braking I got a clunk. Tried suspension, brakes, you name it. Turned out to be the downpipe hitting the brace thanks to soft factory motor mounts allowing everything to move and just touch enough to cause a noise. .20 worth of washers fixed it!

 

if its pad shift,do you know if there is any method to really see this is the problem and if it is is it dangerous? i would think theres no problem, but im no expert at all, thks

 

IRON ROTOR RUST....new group...no rock...just big knock in reverse

 

Not sure about others, but my problem is definitely not rotor rust. From my experience noise from a "stuck" rotor happens as soon the wheel starts to turn (either forward or back). My thump (and suspension movement) occurs after I'm already backing up (and while simultaneously turning to the left). Thanks for the idea though.

 

same here, its not rust^ the thump is qhen braking when backing up, no sure about turning left, will try and see if that way i can replicate it, will post results.

 

I think this might be common w/ cars in general. My Hybrid does it, only when backing out of the driveway then tapping the brakes. Does it once only, 50% of the time.

 

This has been a question in my mind as well since I got my GT3 last month. Both the spring noise and the brake noise. I have PCCB and am always worried when I hear a loud noise from down there. This is due to the sudden drop in bank account when they break. Good to hear it's fairly normal.

 

still a mystery!

 

any news on this issue?

 

Just a thought ....but could it be the LSD making the noise??

 

Where noises are concerned being certain about the location is never easy for me. In this case however I'm pretty sure that it's coming from the front suspension versus the rear end. I still haven't found the culprit but intend to keep up the search. Thanks.

Rocky

 

It sounds like a backlash problem to me.. also may be worse when cold or hot so try at these seperate times. There are a few things that may cause this backlash noise, the flex plate, the rear diff and possibly propshaft, and inside the tranny. I really wouldnt worry about it as a little backlash is normal..

Try this.. Engage Clutch put in first. Englage cluch put in neutral, engage clutch put in reverse. If you hear the thunk then its more or less a bit of backlash.. happened often to me in my car..

The lack of sound dampening, tight spec and performance parts that these porsches come with, it does not seem out of the ordinary for some thunking to occur when going into reverse.

If the dealer has checked it out and your axel, tranny, etc.. bushings and such are all ok then just be a little mroe careful. Also try this.. to stick it into first gear first then give it a rev in neutral before going into reverse.. may help some..

 

had the same problem with my gt3. rear swaybar was loose. had the dealer tighten all suspension components.no more noise.

 

951S. Thanks, good thought. I've had a similar backlash problem with other cars. My GT3 however seems fairly tight in this regard - not much play at all. I think sheep is correct and it's a loose suspension component that the dealer had not been able to find as yet. A couple of questions sheep; did you hear your sound coming clearly from the rear (since it was the rear sway causing the problem)? We've been concentrating on the front thus far because the clunk seems to be so clearly coming from there. Also, could you notice any actual suspension movement associated with the noise? I can and it's the most disturbing part of this issue.

 

thks for the input, i have been to the dealer 3 or 4 times, and they havent found anything wrong, they heard the noise but cant find the source, my worry is that after warranty is over, this problem comes out and its a major thing, as well as the obvious safety issue. been to the track once and everything behaved normal.