Bearing/rotor like noise but not either???

[tjgorn01]

I recently replaced both front wheel bearings in my 05 Aviator AWD 4.6L due to a bad LF wheel bearing. I still have a bit of cyclical grinding like sounds when coasting with VERY little feedback in the brakes/steering. Thought it might be the rotors.

Checked the rotors/pads and while the rears had a very slight warp it was not enough to worry about it. Since I had to replace the pads I put on all new drilled/slotted rotors and ceramic pads.

Noise is still there. It is noticeable as soon as I start coasting down and especially below 40mph to a stop. I can't hear the sound when under power. The sound doesn't change when the brakes are applied - so I don't think it is bearings again or rotors as the feedback into the steering is minimal.

Any thoughts? Drive shaft/U-joint? Sure seems to be coming from the front of the vehicle.

Thanks

 

[4pullingGM]

Ive replaced bearings in the front diff before, sounded an awfull lot like front wheel bearings, front tires that are chopped can make alot of noise as well.

 

[tjgorn01]

Thanks - tires look great. Anyway to know if it is the front diff bearings and check them?

 

[4pullingGM]

Put it on a hoist or jack stands so that all four wheels are off of the ground. Have someone put it in gear and duplicate the noise. Then use a stethoscope and take a listen at different places until you pinpoint the source of the noise, where the noise is the loudest will be the source.

 

[pet575]

I have this exact noise in mine and it is the front differential. I unhooked the front driveshaft since I have AWD and the noise went silent immediately. Easy test. Try it.