El Dario Loco

Since I bought my 07 TT I've had this clonking noice when I lift off the gas at low speed. Thought it was my trans mounts getting old. Replaced them recently with semi-solid ones from Torque Solution but now the sound has actually gotten worse, louder and more frequent. Could it be the engine mounts causing this, and with the harder trans-mounts the strain on them has increased? Any other ideas?


/Darius

estrellajon

Check engine mounts and differential mounts too

nzskater

I had this on my 07 tippo. Replaced transmission and engine mounts (went with Rennline tuneable engine mounts) and a lot of it disappeared. I still get a slight noise when lifting off, but figure it's the sound of the gearbox. Hadn't thought about diff mounts...

jcnesq

Check rear sway bar, could be loose. Had that happen on my prior 996 Targa.

quick968

It's possibly your CV joints.

Tarooki

Is the car a tiptronic or manual? I would recommend changing the "doughnut" flex disc that connects the front Carden shaft to the gearbox, could be a cause.

Porsche does not sell it separately so you should order it from fvd. I have attached the picture of the part, it's a 1 hour job, and the part is around 100$, here is a link to the part and I think if your a 6speed member u get some discount from Fvd.

http://www.fvd.net/us/en/Porsche-0/9...97TT_07-_.html

I changed it last week and the sound reduced.

Keep us updated on how it goes.

El Dario Loco

Thanks! Will check this out. Could be worth to change it with the next service just in case. Let you know how it goes. It's a manual btw.

El Dario Loco

Car was in for service and diagnosis of the clonking noise. Was told that the noise is coming of the front differential: when they disable the front shaft the noise reduces significantly and when they "wiggle" the diff there is a pronounced clonking. Being told that the front diff needs to be replaced which is pretty expensive.

Want to hear your thoughts. Anyone had similiar issue? I've read about the front diff leaks but I haven't noticed that on mine. Do you really need to replace the diff? Can it be something with the attachement of the diff?

Bskyoon

Interested to hear as well. I have a noise very similar to what you're describing but doesn't sound as bad. However, if I lift off in quick succession (gas, lift, gas, lift) within 2-3s of eachother it's not there...

JG 996T

Not really sure about any of this - but if I was looking at a big bill to replace front diff - I might think about converting to RWD. I've read about it being done, but don't remember details. Anyway good luck.

RayBest

What I've learnt, over the years with the various Porsches (two Turbos Mk1, a 2012Turbo S and a Carrera S 911's and a Cayman S) that I have had, all of the 911's are 997's, I don't like 991's they seem cheaper and too EASY TO DRIVE, is that they are never short of a quirky noise here, or there, but nothing ever seems to come of it. Have it checked out at your Porsche dealer, if they say they 'can't hear it' - get accustomed to it. You'll miss it when she's gone.

El Dario Loco

Some update on this long standing issue. The "clonking" sound got progressively worse after switching to semi-stiff transmounts and RS engine mounts. Had the car in for inspection at my regular indy who isolated the issue to the front diff: it was possible to manually wiggle the diff and when the front drive shaft was mechanically discoupled the sound went away during driving. The verdict was that the front diff was faulty and needed to be replaced or removed.

I went ahead and asked for a second-opinion at another well-renowned shop. Their assessment was that it's nothing wrong with the diff itself. They came to this conclusion by electronically disabling the diff but found that the issue was still there. So they think that it's most problably something wrong with the mounting mechanism of the diff. They also found a crack in the flex disc for the cardan drive shaft ("the doughnut") but didn't think that could be the cause.

Since the sound was there BEFORE i switched to stiffer transmounts and engine mounts (but got more pronounced) I'm thinking that the problem is with the mounting of the front diff (the cardan shaft front carrier?? http://www.design911.co.uk/fu/prod135481/99737593400/) The next logical step should be to replace both the flex disc and the front carrier and see what happens. Would love to hear the thoughts of more experienced people on this. Are there any other components in the mounting of the diff/front cardan that could be adressed? Anyone had issues with the front diff/cardan shaft after changing to stiffer engine and trans mounts??

DocHW

We're you able to solve this problem?

Mine does it too, but it is only noticeably when going really slow, in traffic. Dealership said it was normal.

El Dario Loco

Exactly the same for me. Last shop that checked it said it wasn't anything to worry about, that the diff itself works fine. But it annoys the heck out of me. I'm planning on changing the flex disc and the front and rear diff mounts when the car goes in for service in a few weeks. Will post an update when it's done.

Johnny DB

Great, keep us posted!