2009 XLT. Droning/Growling noise. Sounds like front but could be rear? Bearing issue? TC?

[hunchy95]

I just bought a 2009 Explorer XLT 4WD at auction. 144k miles. Main issue is growling/droning noise. Starts at about 20mph most audible, then changes pitch/volume with speed. RPM does not change sound, same sound under load or coasting, so I don't suspect trans/TC/diff issue. Don't see any leaks from any of those components either, shifts smooth from what I can tell.

Replaced both front bearings cause it sounded like front and had a little bit of feeling on floorboard while driving, but the noise persists. Could it be a rear bearing causing it?

I read about transfer case making a similar noise but idk if TC would be speed dependent? and make noise under load? I read they make the noise on deceleration/coast but I know nothing about TC's.

Another thing I noticed, the two front tires are different, same size Goodyears but different model/tread pattern, one is 104T and one is 104H idk if that matters. After all this time could that be causing it? I'd hate to spend money on new tires and still have the noise.

I appreciate any help and info on this. I've read the other threads about growling and bearing noise, and still consider it could be rear bearings, but wanted to see if anyone has input on other things I should check that are common on these explorers.

Part of me was hoping its not rear bearings because I feel pressing them is going to be a headache from videos I've seen.

Thanks all.

 

[Rcflyer330]

Yes it could be the rear wheel bearings, tires, transfer case , differential, or an alignment issue. To check wheel bearings front or rear get to a speed where the noise is most noticeable and turn the steering wheel left and right slightly. If the noise gets louder turning to one side it's most likely a wheel bearing issue. If it's constant then it's probably tire/ alignment issue. If you have 4wd turn it on while driving see if the sound changes. If it does you know it has to do with the front diff and transfer case.

Having a different tread on one tire I would not think that would cause a noise. You can check your tires for wear and see if you have uneven wear (pressure issue or alignment) then feel the tread see if you have any cupping by running your hand from front to back and back to front. Cupping I believe is when the front of each tire lug is warn more than the rear it will cause a lot of noise like a wheel bearing. If your tires are old they also will get louder with age and it may be time for a new set of tires.

If it is rear bearings and you live in the rust belt it may be cheaper, easier and faster to replace the entire rear knuckle bearing assembly.