Noise from rear of the car? Axle pinion bearing maybe?

**Jknerr** · 04-29-2013, 11:22 AM

Hello all you helpful folks!

I have a strange problem. When I am cruising, holding a constant throttle, I get an oscillating noise from what sounds like the rear end. a whrrr ... whrrr. whrrr noise that is related to my speed. Its barely noticeable at 20mph, peaks at around 55~60mph and starts to drown out above that. Its not effected much by turning, and goes away when I accelerate or decelerate. It seems to get a little worse if on an incline, and goes away if going down hill, (I may be backwards on this.)

Its sounds allot like a bearing. I replaced both wheel bearings, and checked the axles for pitting or damage (no problem there.) I replaced the gear lube with castrol synthetic LSD 75W-90. Noise is still there. Checked, adjusted and eventually removed rear e-brake lines, no fix.

Car is an automatic with 10 bolt factory rear end. 53,000 miles.

My best guess is that this is the axle pinion bearing going out, but, even for a 10 bolt it seems awfully early for that. ANY IDEAS ANYBODY!!

Also, if you know a way to diagnose the pinion bearing that would be helpful.

**Firebirdjones** · 04-29-2013, 03:24 PM

You can check the pinion bearing by grabbing ahold of the yoke with both hands and see if you can move the yoke up and down, in or out etc...if it wiggles at all, even the slightest bit, you found your issue. Another tell tale sign is if the pinion seal is seeping oil. Generally when a pinion bearing is on the way out, and the yoke is moving around (even just slightly) the pinion seal can't do it's job and oil starts to seep past.

Just a couple of scenaro's. Hard to say what your noise could be. Almost sounds to me like you described a typical ring and pinion noise. Some make noise on accel, coast, or float. You described "float" (when there is no strain on the gear accelerating or coasting, and you are just maintaining speed)

**2002ssslp** · 04-29-2013, 05:24 PM

It may also be a tire.

**b.lee** · 05-01-2013, 11:40 AM

Ahhh the joys of running a 10-bolt

**Amtrak** · 05-18-2013, 06:57 PM

sounds like your ring and pinion gear have some wear in them and only a new set of gears professional install
will fix it..

**pajeff02** · 05-19-2013, 11:14 AM

FBJ forgot to mention that most of our cars came from the factory with a weeping pinion seal. However, as he said go ahead and check it for play to see if that is your issue. My Moser 12 bolt is a bit noisy, but I also run a tunnel mount torque arm and that seems to act as an amplifier.