Groaning/whining noise at 30mph

[blacksport325]

I cannot figure this out, I have a low moaning/whining noise from 30-50mph, after that it seems to go away. My outer cv boots have some small tears and seemed to throw the grease out, i'm putting new boots on tomorrow, i've also just flushed differential fluid (no metal shavings or anything weird in the old fluid), any other ideas?

[barry]

Rear wheel bearings, also check your shaft ball bearings and race.
Barry

[blacksport325]

I'm back and forth between replacing the axle or just the boots, i'm tempted to do the axle now and the rear wheel bearings at the same time.

[blacksport325]

Barry, is there anyway to distinguish a difference between these, can I jack up the back of the car and figure out a difference between the ball bearing, race, or cv joint itself? I guess they are so close together there may be no way

[LJ851]

Worn CVs generally dont make that sound. The sound you describe is prob a bearing. Can you make the sound change (accel, deccel,L or R turn, brake)?

[blacksport325]

Accel and decel seem to be the same as with brakes, I believe when I made a right turn it was a bit louder.

EDIT: If this was the wheel bearings, is this just the small ball bearing (looks similar to a skateboard bearing) or are these the big ball looking things inside the outer CV? I'm still not to familiar with what everything is called back there.

[LJ851]

Look up your car on realoem , they have exploded diagrams of all the various systems. It will help you diagnose.

[blacksport325]

Looks like i'll be doing the rear wheel bearings next weekend and repairing the boots

[Sagaris]

The rear bearings look like a "skateboard cartridge-type" bearing but they use rollers instead of a ball because they are VERY wide. 2" wide or so. Just to add my input. I had a noise that I would only get from 20-25 mph. I changed the diff. fluid and the noise has been gone ever since.

[blacksport325]

Ugh, rear wheel bearing didn't fix the noise, and it was a pain to do that. I have a new axle on the driver side, i'll be changing the passenger axle this weekend. I have some amsoil laying around I may change the diff fluid again with better stuff and see if it fixes this noise, if not I may be looking for a new diff.