barlowdo

I have had this sound coming from the right(pass side) rear of my 2001 C4 Cab 996 Tiptronic.

It has been there since I bought the car in April.

I had the garage look at it under warranty thinking it may be a wheel bearing.

Instead they said it was a bent wheel on the drivers side rear that they straightened.

Up until a month ago I really could not narrow down when the sound occurred.

But now I have narrowed it down to occurring around 45 mph on a up hill grade when the car is in 5th. It also may do it in 4th. It goes away in third but only because the rpm's on down shift rise above 2k. The sound happens around 1800 RPM in 5th. If I manually shift it down to 4th or if I am in cruise and it shifts down the sound instantly goes away.

I do not get the sound when accelerating away from a traffic light but than it is not in 4th or fifth and as far as I can tell even in manual mode I can not force the car to start in fifth gear.

Some folks have suggested pinging. Not sure if it really sounds like pinging however.
Maybe something loose in the muffler ?
Maybe a suspension component or rotating part hitting something else as suspension gets loaded?
I have crawled around the area where I hear the noise and see nothing out of the ordinary.

The sound to me sounds similar to a saw blade being dragged across a hard surface. I recorded the sound with my Iphone but not sure I can attach a .m4a file to this post but I will attempt to.

Ok I added a .zip file with name Memo.m4a to this post.

The sounds starts around 25 seconds into the recording.

I might add that it has been doing this sound for 5k miles and no change in sound level or frequency of occurrence.

There are no drips at all under the car from any leakage.

Thanks in advance.

Macster

Best bet is to take a tech on a ride and demo the behavior.

My WAG is going up a hill/grade in 5th (or even 4th) gear you are lugging the engine. The few (darn few) times I've even come close to doing this I've never heard pinging though. But you may be running a different gasoline. I hope it is of the right octane grade and fresh...

I note you you have a C4. My Turbo has the same drivetrain and even in 2nd gear at below 2K the drivetrain sounds a bit of a protest. I avoid large amounts of throttle too.

There have been reports of the cardan shaft/bearings failing so you have to have this possibility checked if the ride along tech doesn't find an explanation for the noise.

You really can't do much with the car on the ground. At the dealer or wherever get the car in the air and check all heat shields, exhaust pipes/hangers/etc for any looseness. Use the heal of your hand or a soft mallet to tap on the more substantial items listening for any noise that can arise from something being loose or cracked.

Hurdigurdiman

I take it you are the same poster who made this posting a while back now. If so/or if not so, I have said it before and will say it again. No matter if you have a triptronic car or not, if you or your stupid trip set up, labor/lug your engine in the wrong gear and your revs drop below 2000 revs (not cruising but under the slightest acceleration) then you are asking for trouble. You dont do that in any car never mind a Porsche. If the triptronic wants to do it, then knock it back into manual and overrule it. It speaks for itself when you down shift 'the sound goes away'. DUGH BLOODY DUGH. So go ahead and pay to have a so called bent wheel straightened. Drive the car around in a high gear and have the revs below 2000revs and do your recording. Try slowing down even further and then you will feel the engine humping and jumping liker a kangaroo until it stalls out on you. OR never let the revs drop below 2500 and I bet you dont hear the sound again. Right I am going to bang my head on the nearest wall now... And don't reply to my posting please. I hate when people who dont know how to drive a manual car simply **** me off. Even my wife is saying to me... "see I dont know why you are getting involved in this posting". Drive it in manual and keep your revs somewhere between 2500 and 3500.

Doesnt this statement tell you something.
I do not get the sound when accelerating away from a traffic light but than it is not in 4th or fifth and as far as I can tell even in manual mode I can not force the car to start in fifth gear.
Ok its head banging time for me...

barlowdo

Macster, Thanks for the help.

Hurdigurdiman, Please keep your nasty comments to yourself. This is considered to be a technical forum for folks to come to for help. Not to come to and hear your slams. Showing an icon of a head pounding against a brick wall in no way negates the rudeness you display to other posters.

I scanned through your other posts and I am not the only one who has asked you to back off.

Barn996

Having a Porsche savvy mechanic take a ride would make sense. Maybe he can duplicate the sound you are hearing while driving, then put it up on a lift. GL with troubleshooting.

TCR

I had this exact same noise after having my 01 tip trans replaced for a different issue. To me it sounded almost like some type of heat shield rattle. It turned out that the replacement trans had a defective bearing. While you are under warranty, I would seriously have them take a close look at this as it is crazy expensive to replace the trans and they cannot be repaired. (that is what the dealer told me). Mine was luckily replaced under warranty.

OGWGFIW

Tranny mount possibly? One of mine was bad but I wasn't getting any noise from it.

Moderators, how long do we have to listen to these negative posts from Hurdi?

Barn996

^ A long time so it seems.

Hurdigurdiman

Simply read. Don't listen... These are my honest opinions same as yours. Right or wrong, they are mine and I will continue to post my opinions.

OGWGFIW

This is a tech advice forum not an attack forum. You can make your points without all the negativity.

Sneaky Pete

Hurdi is from across the pond.......they all talk like this.....http://www.youtube.com/watch?feature...&v=wJtU4k2UMAU

Hurdigurdiman

Well that shows that you are not the only D H on these pages then doesnt it? I dont see anyone disagreeing with what I am saying.. Only disagreeing in the way I am saying it. Again I can't wrap something up in cotton wool just to suit a poster. BTW Nice one Sneaky Pete lol.

barlowdo

"I had this exact same noise after having my 01 tip trans replaced for a different issue. To me it sounded almost like some type of heat shield rattle. It turned out that the replacement trans had a defective bearing. While you are under warranty, I would seriously have them take a close look at this as it is crazy expensive to replace the trans and they cannot be repaired. (that is what the dealer told me). Mine was luckily replaced under warranty."

Unfortunately the warranty is long gone now. Although I addressed it under warranty at the time and the garage thought it was they wheel as mention previously.

My fault for not pursuing it further but at the time I had to leave on a trip and did not have the option to take it back to the shop. I did not think it was a big issue at the time. Mostly thought it was a wheel bearing.

Byprodriver

The course of action I adopted a long time ago is to never respond to his frequent threads asking for help!