Hello all,

I just took my 11 997.2 tts out for a drive and noticed that during deceleration there is a very noticeable whining sound from what sounds like the rear of the car, however it's difficult to be sure. I let the fluids warm up but the sound is still present. Oil level is good, no codes, and the car seems to drive fine otherwise in all modes. The only mods are muffler delete and springs. I have also ruled out tire noise.

I have seen a few forum post on the matter, but I failed at finding anything specific to the 997tts.

The nearest Porsche dealer is 200 miles away, so I am reluctant to drive the car down there.

Any thoughts or suggestions?

Thanks!

 

I take it the whine is new? Both of my cars emit a bit of tranny/diff whine but not enough to worry about.

Unless it is obvious to you the noise is not normal you might have to enlist the ears of someone in town who has some good knowledge of what healthy and sick transmissions/diffs sound like even if he is not able to repair the Porsche transmission/diff if it proves sick. If he says it is "sick" then you are looking at a flat bed trip to the dealer to have this looked into.

The noise might be a wheel bearing, or even tire noise. I do not know how you can rule out tire noise.

My 996 Turbo had a whine at speed that had my suspecting wheel bearing and I took the car to handy -- well 140 miles away -- dealer (in OKC) and the tech there checked the car over and told me the noise was from the front tires. He showed me -- had me feel actually -- the tread blocks of the front tires and sure enough I could feel the feathering and see the scrubbing take place. A drive home nearly 1500 miles away and an alignment had the noise gone after driving some more and scrubbing the tires in to the new alignment.

Also, my experience is worn tires can generate some considerable noise.

Anyhow, is the noise present in all gears or at least a couple of the higher gears? If you put the tranny in neutral does this affect the noise? If a manual transmission if you press on the clutch does this affect the noise?

 

I have had a wheel bearing do that before!

 

Yes, the whining sound is new, and very noticeable. I had driven the car three days prior and didn't notice it then. I suppose it's possible that the whining sound was present at that time, but I'm one of those guys that typically notices if anything is "off" each time I drive the car.

I finally had some time to get back to this and with the help of a friend. I have found that the "whining" occurs in all gears. Furthermore, the pitch and tone changes with the speed of the car and not with the RPM's. I put the car in neutral at speed and the sound remains. There doesn't seem to be any change whilst driving in reverse or going around corners.

I started to second guess my statement about ruling out tire noise, but the sound occurs on different surfaces e.g. blacktop, concrete, etc. I'm no mechanic, but it does sound mechanical in nature.

The dealership is picking the car up this week. We will know soon enough where the sound is coming from.

Thanks for the input!

 

Update -

After an extensive inspection and tests with sound equipment, it was first discovered that the bolt holding the left side lower control arm to the body of the car was very loose. This was detected when checking for play in the bearing. This loose bolt allowed nearly 1/3-1/2 inch of play left to right. This hub movement translated to movement with the left front half shaft, which in turn put stress on the gears inside the differential causing them to wear aggressively. Through the use of Chassis Ear sound diagnostic equipment we isolated this sound to the gearbox. It was also discovered that fluid seepage was all over the left side output of the differential when it had flung gear oil while this output flange was being pulled and pushed.

A new diff and will be installed.

Hopefully this information is useful.

 

Thanks for the update.

Wonder how that bolt came to be loose? Just bad luck I guess.

 

I suspect we'll never know. Bolts come loose all the time, right?

But.............I am told, however, that the bolt in question must be replaced with a new one once removed. When I bought the car (CPO'd) it had GMG springs, and unknown to me until now GMG bushings. Perhaps I should have been more thorough with my inspection and not relied on the CPO alone before purchasing this car. Lesson learned!

It has been explained to me that to install springs and bushings this bolt must be removed, and therefore any warranty claim would be declined due to outside influence. I'm not privy to the internal discussions (PCNA & dealership) that ensued, but the dealership that certified the car is repairing the car at no cost to me. I'm no expert, but from reading other stories regarding aftermarket parts, it seems Porsche would have a hard time proving the springs and/or bushings lead to the diff failing.

I am very thankful to the dealership to say the least. I kept these details to myself while working towards a resolution, as not to inflame the situation should anyone from the dealership read the forums. Now you know.