Driveline whine

Just today my car developed an annoying whine in the driveline. It varies with wheel speed, not RPMs. I can hear it anywhere above 5MPH or so.

It is not tread noise and tires are inflated to their normal pressure.

It's loud enough that my friend who rides in the car with me occasionally noticed it right away.

It sounds like it is coming from the middle or rear of the car. Someone suggested U-joints.

I replaced both U-joints in November along with a CVPI driveshaft and extended tailshaft housing.

I'm worried it may be related to the differential or axle bearings. The gears and carrier were replaced in January by a professional Ford technician and weekend racer and all bearings looked good so we did not replace any.

Could bearings just suddenly go bad and cause this noise? How would I know if it is bearings or U-joints or anything else?

Just today my car developed an annoying whine in the driveline. It varies with wheel speed, not RPMs. I can hear it anywhere above 5MPH or so.

It is not tread noise and tires are inflated to their normal pressure.

It's loud enough that my friend who rides in the car with me occasionally noticed it right away.

It sounds like it is coming from the middle or rear of the car. Someone suggested U-joints.

I replaced both U-joints in November along with a CVPI driveshaft and extended tailshaft housing.

I'm worried it may be related to the differential or axle bearings. The gears and carrier were replaced in January by a professional Ford technician and weekend racer and all bearings looked good so we did not replace any.

Could bearings just suddenly go bad and cause this noise? How would I know if it is bearings or U-joints or anything else?

SInce you mention that it is not rpm related I assume it does not make a difference in whining when you let off the accelerator.

Usually a growl with indicate a bad bearing.

A bad u joint usually has a vibration to it.

It might be worth puttting the rear end up on jack stands or go to shop with hoist so you can try to pinpoint where the noise is originating from.

I wish I had a lift to get it on but I am at college and don't have jacks around here (they're back home several hours away) and no friends with a lift.

I did take some driving videos yesterday to demonstrate what I am talking about. In both videos you can hear it vary with the speed and letting off the gas does not change the pitch of the noise so I think this may be a good sign that it is not a backlash problem with the gears.

http://www.youtube.com/watch?v=lX3lNOuWdDs
http://www.youtube.com/watch?v=IFD9SJsC5xU

I wish I had a lift to get it on but I am at college and don't have jacks around here (they're back home several hours away) and no friends with a lift.

I did take some driving videos yesterday to demonstrate what I am talking about. In both videos you can hear it vary with the speed and letting off the gas does not change the pitch of the noise so I think this may be a good sign that it is not a backlash problem with the gears.

http://www.youtube.com/watch?v=lX3lNOuWdDs
http://www.youtube.com/watch?v=IFD9SJsC5xU


Sorry, I can not hear the noise on the video's. My hearing is not the greatest anymore but it doesn't seem like the volume of the vids are high enough.

I don't know what to tell you, Does it make a difference if you swerve to the left or right, best if you do this on a open road lightly traveled and swerve fro lane to lane looking for a change in bitch.

I think you meant pitch ;)

But swirving does not affect it. Others have told me they believe it is the pinion bearing. I guess I have to take it all apart again.

What would cause a bearing to suddenly start making noise if it gave no indicators of failure before?

I think you meant pitch ;)

But swirving does not affect it. Others have told me they believe it is the pinion bearing. I guess I have to take it all apart again.

What would cause a bearing to suddenly start making noise if it gave no indicators of failure before?

Yes you are right, I mean't pitch. I would call around to see what it would cost just to lift the car on a hoist and diagnose rather than throwing parts at it.

I found time to finally get it on a lift and take it apart. It was what I initially suspected - the pinion bearing. Or to be more exact, the pinion bearing race. The race seems to have cracked and a piece flaked off. The bearing them generated a bunch of noise and friction on that broken surface. No other damage has occurred, luckily. I replaced both pinion bearings and races and re-set the backlash to .010" and the pinion preload to 18 in-lbs. No noise woohoo!

http://a5.sphotos.ak.fbcdn.net/hphotos-ak-ash4/229318_10150184669126107_605211106_7056137_1408282 _n.jpg

http://a5.sphotos.ak.fbcdn.net/hphotos-ak-ash4/226266_10150184669431107_605211106_7056142_5504164 _n.jpg