kj217

my car has a low pitch humming/whining noise,, i guess from rear end,,
it happens @ 45-50MPH on 3rd and 4th gear,, and @ 35-40MPH on 5th gear,,

the car ran 35k miles only,,

any ideas?

Macster

If noise constant under throttle or coasting a wheel bearing. When safe to do so weaving the car rather sharply first one direction then the other if this makes the noise change noticably a wheel bearing becomes more likely.

If the noise changes appears to be tied to the car accelerating or deaccelerating -- under closed throttle coast down -- then the rear end (differential) comes under strong suspicion.

Added: The noise could be transmission related. The Tip if low on fluid or with too old fluid or the wrong kind can make noises. Where safe and noise present release gas and shift transmission into neutral. This almost eliminates the tranmission from the equation.

Are tires inflated properly? How old are the tires? Proper (N-rate) tires can get hard with age and heat cycles and when they wear make a heck of a racket.

Are tires the right kind of tires? N-rated? Same front and back, side to side?

Different brands/styles of tires can make different amounts of noise. If tires the cause of the noise my experience is the noise will be present or more pronounced on some road surfaces while absent or barely discernible on other road surfaces.

If the noise does not appear to be connected to road speed but appears to be tied to engine speed, could be something engine related, or accessory drive related. Beyond that...

Is the same car with periodic rpm drop? If so then I think the car's possessed!

Sincerely,

Macster.

fbgh2o

As usual, Macster has a lot of good suggestions to investigate.

Are you sure that the noise goes away above those speeds? My pinion bearing was going and the spyder gears were pitted in my transmission and it produced a similar effect, most noticeably in 4th, 5th and 6th gears under moderate engine load. However, the whine was also audible at constant speed as well. I hope that it is not that for you.

Barn996

If it's whining, it wants to go faster.

kj217

the noise is present in speed ranges i specified in both accelerating and decelerating but,,to higher pitch on acceleration,, to lower pitch on deceleration,,
the noise only happens if i traveled really slowly through the speedometer,,

the Tip fluid is factory fill since the car assembled,, level is ok,, dealer wouldn't change it before 60k miles.

my tires are brand new, Y-rated and inflated @ 35 psi

i, totally, agree!

Macster

Based on the info you've provided I'm going with the differential.

But you're still faced with having to have some qualified person make his own diagnosis and then acting upon that to fix the problem. Knowing what the problem is -- even assuming I'm right (and my confidence level is not that high) -- is not going to make the problem go away.

The car is need of attention by a qualified Porche technician.

Or, the car needs a young priest and an old priest.

Sincerely,

Macster.

kj217

the priests will make more sense than my local dealer

kj217

i only wonder why the speed where the whine happens is around 45mph on 3rd and 4th,, but it happens @ 40 in 5th.

RPMulli

i agree...

Sneaky Pete

I don't have a Tip but the only time I'm going 40 MPH is in 2nd gear to 3rd. Maybe you should start to stay in a gear longer before upshifting?

Shark Attack

start with the simple stuff, tires and alignment

Pac996

kj217 my attitude is the car has a drive train and is going to make noise. After multitude of sport and performance cars I expect to have gearing noises. It aint no big thang maannn. Well unless you get clunking and and dinging noises.

kj217

phew,,

MagnusB

What happend to the "I have the same sounds coming from the passenger seat, it's the wife" comments?

Is it a hissing or whining sound? My car started hissing, it's the power steering, next thing going I guess ...

Sneaky Pete

Well in that case my passenger seat WON'T SHUT UP! I try to put the windows down to drown it out but the volume just keeps increasing! did I say that?