Diagnosing Rear Differential Noise

[glenmorebuckman]

Ok. I have a 2002 XLS 4x4 Explorer 4.0 which has suddenly started making noise in the rear area of the vehicle.I have tried to identify where the noise is coming from but from inside the vehicle it sounds like it's everywhere in the back. It starts out as a low rumble going down the road and then starts to make a loud humming noise the faster you go. Turning corners makes no difference in the sound. Is there some way to jack the vehicle up and place it on jack stands and put the vehicle in gear and be able to tell where it's coming from? I worry about it being 4x4 auto. Is there someway to disconnect the 4x4 auto so this can be checked in this manner. I'm almost certain it's the rear diff. but don't know any other way to check it and be sure.

 

[Number Twelve]

Look for, "Brown wire mod" to defeat the auto-4WD engagement, or play it safe and jack the whole car up. I believe I'm going to have to do that to find the growl in my car, but not until the weather gets cooler!

oh yeah, there's a couple of fuses you can pull to stop the 4WD.

 

[Donystoy]

The first thing to check is the rear wheel bearings. Just jack up the rear end and see if there is play in the wheel. I have replaced both of mine in the last couple of years. The last one I did was not very noisy for some time but when it got a lot worse I checked it out. Found lots of play and metal savings. The rear differential in these vehicles are also prone to been noisy.

 

[mbed]

Hi,
Does anyone know if it possible to drive a 02 with AWD in 4High using front wheels only if the driveshaft to rear is removed?
Thanks!

 

[Number Twelve]

From what I read, AWD means continuous 4WD. It seems logical that you can run the fronts, only.
Then again, I'm only talking about what I read on the Internet...not because I know for sure.

 

[Alan at work]

Hi,
I have a bad wheel bearing on an 03 Eddie Bauer. Just spent all day getting the stub axle off. Then I broke my snap ring pliers trying to get the bearing retainer clip out. I originally suspected Universal Joints but they feel good. Then I thought I would check the wheels. Whoa! lots of play on the right side. Stuck out like a sore thumb. But prior to that I thought the center of the drive shaft (under the boot) had a real slight amount of play in it. Still not sure if I'm gonna investigate further until I get the wheel bearing done. Think I'm gonna pay to get the bearing switched out because I have no press. I'll prolly let them get the circlip off too.

 

[Number Twelve]

Still not sure if I'm gonna investigate further until I get the wheel bearing done.

One of my standard rules: Do the obvious first. By the time you get done with that, your brain will have processed what's supposed to be next.
Besides, the obviously bad part is the one most likely to disassemble itself without your consent.

As for the snap ring? You're going to have to take it to a shop to get the bearing shoved in, so they will do the snap ring for you. Youtube vids show NOT using snap ring pliers. Wedge it out with a screwdriver or two...or just take it to the place with a hydraulic press and let them to this tiny, incidental chore.

 

[imp]

Ok. I have a 2002 XLS 4x4 Explorer 4.0 which has suddenly started making noise in the rear area of the vehicle.I have tried to identify where the noise is coming from but from inside the vehicle it sounds like it's everywhere in the back. It starts out as a low rumble going down the road and then starts to make a loud humming noise the faster you go. Turning corners makes no difference in the sound. Is there some way to jack the vehicle up and place it on jack stands and put the vehicle in gear and be able to tell where it's coming from? I worry about it being 4x4 auto. Is there someway to disconnect the 4x4 auto so this can be checked in this manner. I'm almost certain it's the rear diff. but don't know any other way to check it and be sure.

@glenmorebuckman
Yes, you can place 4 stands under the frame, and run the 4X4 in gear, listening with a stethoscope (long screwdriver works) at the suspected noise locations. Have someone run in D, easy on the gas, let it shift up to about 30 mph.

Use 4X4 HIGH not AUTO. You can definitely pinpoint the source by checking at the knuckles (wheel bearing noise) and the center section. Check there on bottom side, front, under the pinion, then side, to differentiate between pinion bearing and ring gear/diff brng noise. It will be loudest at the trouble spot. imp