Noise in Rear End on 2014 Ford Explorer

Hi. I have a 2014 Ford Explorer 4WD with 134400 miles on it. It has developed a noise in the rear of the vehicle that I can’t seem to figure out. My initial thought is that it is one or both of the wheel bearings but here is what I have done to troubleshoot the issue. I have jacked the vehicle up and moved each wheel back and forth but there is no play in the wheel. I have checked the brake pads, rotors, calipers, etc. and they are good (recently replaced.) There are no other rear end parts that are loose or broken, it actually had recall work done on some of the rear suspension parts. I thought it might be something exhaust related and had replaced both mufflers due to them rusting out. I verified that there are no holes in the exhaust system. The noise sounds like a growling noise that gets louder and higher in pitch as the vehicle goes faster and doesn’t start making noise until about 20 MPH. The noise gets louder with vehicle speed and not engine RPM so I am not thinking that it is an exhaust issue. The tires are not wearing unevenly and there is no swaying when I am driving it at highway speeds. At this point I am leaning towards wheel bearings but I don’t know what else it could be. Thanks.

The noise may be coming from the rear differential.

When was the last time the diff fluid was serviced?


Thanks for the info. Supposedly it was changed at the dealership prior to us buying it but honestly I don’t know if it really was or not. I will check that out.

Without being able to drive it and hear what you are hearing, I would recommend rotating the tires (front to back) to see if the noise changes at all…

But you can also jack the vehicle up and spin the wheel by hand to see if you can feel any vibration in the coil spring… Depending on the safety or not, if it is an AWD you can even (with all wheels off the ground) run the vehicle in gear and feel the coil spring for vibrations…

Also maybe buy/try some chassis ears and see if that helps…

That doesn’t help us since you did not tell us when you bought it.

Could very well be pinion bearing noise. A greasy differential is a big clue. Low diff fluid is an even bigger clue that your pinion and carrier bearings in the diff ran short of oil and now need a rebuild.


Thank you for the information. I will try that.

Hi. Sorry. We purchased it in July 2022. Thanks for the info.

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Wheel bearings or differential (as mentioned) is what I’m thinking about. Does the noise change when you turn the steering wheel? And there are no strict “rules” about it, but wheel bearing noise often likes to peak in the 45-55mph range. And it does change when you turn and load up or unload one side. Also often tends to sound like you’re being stalked by a small airplane.

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Me too. I own an older Ford 4WD truck, but only noise from rear I’ve had to deal with was a chirp/squeak sound caused by a driveshaft u-joint. A growling sound that gets louder the faster you go is the exactly symptom I had on my VW Rabbit, turned out to be worn out front wheel bearings. Manually turning the wheel in the shop didn’t demonstrate anything wrong. The only way I knew it was the wheel bearing is replacing them solved it. Your rear wheel bearings are probably lubed by the same gear oil that lubes the differential, so first step is to make sure the differential gear oil is at the proper level.

I wonder if irs diffs are more prone to issues vs solid rear axles?

IRS diffs don’t handle heat as well as solid diffs because they contain less fluid. And if they leak, they have less fluid in them so they run dry sooner. The seals are exactly the same… The cover, the pinion and the axle seals and all can leak at some point.