Noise after suspension work on a CD5
 

A friend of mine and I changed the ball joints (upper and lower), outer tie rod ends, stabilizer links, wheel bearings/hubs, rotors, and axles. We changed the axles for good measure since we changed almost everything else. But when I took one of the wheels off, I realized that my friend forgot to put the axle nut the last time we worked on the car. So after the axle change, while the car is in motion, it makes somewhat of a low-pitch grinding noise during acceleration, deceleration, and while in neutral. Anyone have a clue on what it could be? Not sure if the absence of the axle nut caused any damage to the new parts that were installed a few days before.

So was the noise there before or after all of the parts were changed,,,,and I hope the axle nut is back on. By the title I have to assume the nosie came afterwards.

Recheck the pads/calipers and inspect the bearings.

To be honest, it's hard to say because prior to changing the axles, my car had a wheel bearing problem (vibration), so the noise might have been "covered up" by all the vibration. Initially we were only gonna change the ball joints and tie rods, but since I already had the wheel bearings, we changed them a day later. The noise caught my attention as soon as my wheel bearings were replaced, so my next assumption was to changed the axles since we replaced basically everything else. When we began the axle change, that was when I realized that we forgot to put the axle nut back on. So now that everything is replaced, I really don't know what else it can be.

Again be sure the caliper and rotor are "clear" of everything....be sure a backing plate didn't get bent.

From there, remember this is the net and I can't hear the noise, it does sound like a bearing issue.

Did you do both sides, if so can you pinpoint which side grinding is coming from? Also, if you still have old axles, replace the side that did not have the nut on if you have doubts.
Like said, make sure you don't have a stuck caliper and you hear pad against rotor noise.

Yes I did both sides. And no, I no longer have the old axles. I checked the noise to the extent of even putting my head behind the hub assembly (with the front end on jack stands) while accelerating, and the noise is definitely coming from the axle/diff. on the passenger side. But since the axles are new, I don't suspect the axles being the problem.

Ok, now if you lift pass up and turn the wheel by hand, any grinding? Also, does the noise change when you drive straight, turn either way? Looking under the car, anything that can rub against the axle?