stratonick

Just picked up a 2004 Certified Preowned 350Z (Manual 6 Speed) from Flemmington Nissan with 41K miles on it.

Everything seems fine except from the moment I start driving it in the morning until it fully warms up (approx 10-15 Minutes) I hear this strange "Whirring Noise" from what I can only assume is the rear differential... as soon as the car is FULLY warmed up this noise ceases.
Also, this sound will only occur when the car is moving....if I rev the engine a bit in neutral I dont hear anything unusual.
Any ideas? I know that the Enthusiast Edition (which is what i have) has a "viscous limited slip" read diff. (whatever that means....basically posi-traction i guess) but has anyone else ever had this issue?

rbo1577186

How are you sure it's the diff?

stratonick

I'm not sure of anything..... but I'm hoping that someone else here may be able to give a point in the right direction.
Also, there are no other issues that i can find, the car brakes fine, wheels are ok, exhaust is tight, the sound I'm hearing is definitely coming from somewhere in the back / underside of the car.
This only happens in the morning, as soon as it warms up its gone. The brakes dont really warm up unless used quite a bit, and the sound doesnt change if i use them or not, and the exhaust pipes get hot within 3-5 minutes or so, and i hear this "whirriing" long after that.

Dont really know what else it could be.....

rbo1577186

You need to put it up on a lift or jack stands or something and pinpoint noise. You can remove the driveshaft to diagnose the diff or brakes. If it still persists, its in the tranny somewhere. You can use a long screwdriver as a make shift stethoscope to find the noise. Put the blade end on the diff or tranny (if on a lift) and the handle at your ear. Where the "whirring" noise is loudest, and you will find where your problem lies.

Check your fluids also to eliminate that possibility. This is a vague description, so I don't know any other way to track it down.

stratonick

UPDATE - Just got my car back from the dealership last night.....

Ok so i picked my car up from the dealership today after it was there for a little over a week.
They said that they wernt able to pinpoint where the whining sound was coming from but they replaced the "pilot bushing" and the "throw-out" bearing thinking that was the issue. Now i have my car back, the whineing sound SEEMS to be gone. But now the clutch is "rough" either starting out in 1st gear or reverse. It was VERY smooth to engage the clutch in ANY gear BEFORE i dropped my car off to the dealership.
It almost feels like the clutch is "shaking" when i let the pedal out into 1st or reverse gear. No matter how little / how much throttle i give it (usually dont need much to get into 1st gear). If i rev the engine up to about 1500Rpm then there's no rough/shaking when starting out in 1st, but my guess is that either the tech. who drove it had NO idea how to drive a standard shift car, or maybe there's some kind of clutch adjustment that didnt get done after the new throwout bearing was installed?
Either way i called the dealership on the way home and let them know that after christmas i'm going to be making a return visit so this can be fixed, but I'm wondering if anyone else has any knowledge on this, I dont want to walk back into the dealership without some info to tell them.