I started noticing some kind of "metallic hiss" noise coming from the drivetrain about 5,000 miles ago. I have about 116,000 miles on the car right now. The noise is there when the car is in motion i.e. the wheels are moving. The noise isn't there at idle, the noise's pitch doesn't change with throttle (rules out engine maybe), and the noise's pitch doesn't change whether or not I'm in gear (rules out tranny, gears, clutch). When I start accelerating from a stop, you could hear the noise getting a bit louder and as the car approaches a stop, the noise dies down and stops when the car is fully stopped. The noise isn't really loud or anything, but you can sort of notice it if you're looking for it. It isn't a "whine" noise, but like a noticeable hiss and one could certainly not notice it if one wasn't paying attention. What could this noise be? The diff? How would you know if the diff is failing? From what I've read on the forums, the only noise that people have heard indicating impending trouble, was a "whine", but mine isn't really a whine, more like a metallic hiss.

 

Best way to tell if the diff is failing is to change your diff fluid and look for metallic shavings or pieces of metal on the diff drain bolt since its magnetic. The diff fluid itself should be dark and clumpy, so try to see if pieces of metal might be in that also.

 

Thanks for the reply. So obviously, finding metallic shavings in the oil would be a certainty that the diff is going bad. Is it true for the converse? If the diff is going bad, will you always find shavings in the oil? In other words, if I don't find shavings in the oil, does this mean the diff is ok?

 

Torsen diff characteristically whines at low speed. If it grinds, then you have a problem.

 

When I brought the car to Billman250 earlier this month for the CR suspension install, he guessed that this noise was coming from the tranny after taking the car for a drive. As mentioned above, the noise is directly related to the wheel speed of the car. And although the noise does not depend on whether or not the car is in gear, Bill said that there is a part of the tranny that always spins with the wheels.

Fast forward to yesterday (Tuesday). I brought the car to Huntington Honda for an oil change and had my tech look at the problem. Btw, if you don't need major work done, can't wait for an appt with Billman, and live in western Suffolk county, I recommend going to Huntington Honda and asking for "Bobby M" to work on your car, he's a good guy. Obviously when you can, you should use Bill. Anyway, he put the car on the lift and had someone else drive the car to around 50 mph while he stood underneath the car to see where the noise was coming from. It sounded like the noise was coming from the tail shaft section of the transmission and he said the noise was most likely from metal pieces floating around. So seems like Bill was right.

I can't really describe this noise. It really isn't a whine. You know how an airplane engine sounds like when it's coasting along at like 10mph after leaving the boarding area to head to the takeoff runway? Kinda sounds somewhat like a meat slicer too.

http://www.youtube.com/watch?v=3DaxPw2tskQ

The first half of that video when the plane is just coasting along... ignore the bassy low tone part and focus on the high-pitched shrilly noise. That's how my problem sounds like. Like that, but obviously not that loud. I daily drive this car, so I picked up on this problem when the noise started happening, but this noise isn't so loud, that someone could possibly miss it if they weren't looking for it.

Anyone else have this problem?

 

w0000w, if I didn't know any better, I'd say you were in an airliner and it was about to take off. Let us know when you find out what the cause is.

 

I have this sound too.