Strange Humming Noise From Rear....2002 Explorer

[gbranh]

My wife's 2002 Explorer XLT, 4.0L, 4x4 has developed a humming noise from the rear of the truck, concurrent with wheel speed. Putting the tranny in neutral at speed does not make it go away, nor does putting it in 4HI. The tires look fine, and a cursory visual inspection of all 4 rear CV boots suggests that they are in good shape, as well.

The truck has 110,000 on it, and the tranny has recently been given a clean bill of health by a local, trusted tranny shop. I don't believe it's brake-related, but I'll inspect this weekend.

I remember a similar noise on a Saturn VUE we had several years ago. That turned out to be a bad wheel bearing. I wonder if this is the same situation?

Is there a common failure on these trucks with respect to wheel bearings? I've never done anything with the rear IRS on these trucks, so I don't really know where to start looking.

Thanks for you help,

Greg

[Yamvip]

It could be the bearing or the rearend????

[thepotroast]

The rear diffs on the 3rd gen's are notoriously loud. There is a common occurrence of worn gears and a bad differential clutch pack in the 02-05's, so much so that Ford put out a TSB on it and replaced rear ends making the howling if the vehicle's were under warranty. They serviced and replaced my rear diff internals at 60k miles.

However, a constant humming regardless of acceleration or speed sounds more like a bad bearing, whether it be a diff bearing or a wheel bearing at the hub assembly. The differential whine associated with worn gears and differential clutch packs usually occurs at certain intervals in speed, and goes away when you let off the gas or coast in neutral.

I believe your issue is a bad bearing somewhere back there...whether it be in the differential itself, or at the wheel.

A quick way to check the wheel bearings, is to jack up each side, and try to shake the wheel up, down or back and forth. There should be no play.

[gbranh]

Thanks, guys. I think it's a bearing, as well. I'm going to get it on my lift this weekend, and swap the rear tires while I'm at it, just to make sure the sound doesn't follow the tire. It's definitely coming from the right rear.

I'll report back.

Greg

[Fyrmn88]

I think I may have the same problem, only thing is the noise goes away when I let off the accelerator. Sounds like I have a knobby tire on the rear with all the whinning. So can it be the tranny, bearing or diff? Any help would be greatly apprecciated

[thepotroast]

Originally Posted by Fyrmn88

I think I may have the same problem, only thing is the noise goes away when I let off the accelerator. Sounds like I have a knobby tire on the rear with all the whinning. So can it be the tranny, bearing or diff? Any help would be greatly apprecciated

Differential. Read my post above and it explains the difference between the symptoms. The whine is very common across the board, Ford put out a TSB on the issue and replaced the ring, pinion and diff clutch packs on Explorer's still under warranty under the TSB for it.

[gbranh]

I put the truck up on my lift, and removed both rear tires. Visual inspection revealed nothing conclusive; both inner and outer CV joints looked clean. No play in the hubs when rocking tires in and out and back and forth. Rotating one tire (the other spinning the other direction, of course, didn't reveal anything, either. I then swapped the rear tires left-to-right, and "maybe" the sound seemed to move more to the center of the truck, but that could've been my imagination. I then played with rear tire pressure, to see if I could change the noise, and that didn't really seem to make a difference, either.

I think at this point, I'll change the rear diff lube. Any suggestions on fluids, procedure, etc? I've changed the rear gear lube in Ford 8.8" solid axle Mustangs several times; is this the same? I assume I remove the rear diff cover, flush, and clean, RTV the cover, and reassemble, then fill by removing a fill plug somewhere?

Greg

[mountaineer02]

I would also appreciate the advice asked by gbranh. I guess i could just read my haynes manual aswell. if its not under warranty, any thoughts on parts other then OEM?

[9eye]

Originally Posted by gbranh

My wife's 2002 Explorer XLT, 4.0L, 4x4 has developed a humming noise from the rear of the truck, concurrent with wheel speed. Putting the tranny in neutral at speed does not make it go away, nor does putting it in 4HI. The tires look fine, and a cursory visual inspection of all 4 rear CV boots suggests that they are in good shape, as well.

The truck has 110,000 on it, and the tranny has recently been given a clean bill of health by a local, trusted tranny shop. I don't believe it's brake-related, but I'll inspect this weekend.

I remember a similar noise on a Saturn VUE we had several years ago. That turned out to be a bad wheel bearing. I wonder if this is the same situation?

Is there a common failure on these trucks with respect to wheel bearings? I've never done anything with the rear IRS on these trucks, so I don't really know where to start looking.

Thanks for you help,

Greg

I am gonna bet on bearings, i personally have 2 2002 explorers (a limited and eddie bauer). Between 100,000 and 130,000 miles i have had to chang all 8 bearings on both vehicles. Before realizing this was such an issue on these vehicles i left the humming noise as a loud diff as some above have noted. Eventually the rear right bearing on the eddie bauer overheated so badly it melted the cv boot right off the axle. The quick boot kit used to replace it was not a perfect fit so now my new project for the week will be replacing the axle assembly for that side that now knocks terribly when accelerating and decelerating, yay. Besides my own humble opinion in other forums i have done searching in it seems to be such a huge problem that people are crying for a recall. Personally they do last over 100,000 miles in most cases i have seen so i am not gonna cry for a recall but it does seem to be a very large scale problem as opposed to the differential. imho

[iBrent]

Originally Posted by 9eye

I am gonna bet on bearings, i personally have 2 2002 explorers (a limited and eddie bauer). Between 100,000 and 130,000 miles i have had to chang all 8 bearings on both vehicles. Before realizing this was such an issue on these vehicles i left the humming noise as a loud diff as some above have noted. Eventually the rear right bearing on the eddie bauer overheated so badly it melted the cv boot right off the axle. The quick boot kit used to replace it was not a perfect fit so now my new project for the week will be replacing the axle assembly for that side that now knocks terribly when accelerating and decelerating, yay. Besides my own humble opinion in other forums i have done searching in it seems to be such a huge problem that people are crying for a recall. Personally they do last over 100,000 miles in most cases i have seen so i am not gonna cry for a recall but it does seem to be a very large scale problem as opposed to the differential. imho

Wow, you got 100k+ out of your bearings? that's great. My '05 had to have new front bearings at 63k. I was tempted to buy OEM but if they only last 63k then maybe i'll have better luck with aftermarket. I went with Timken bearings from Rock Auto. Haven't had to do the rears yet (knock on wood).

[hoss_hanna]

the explorers have been plagued by bearing issues since the first gen in 91, if someone tells me they have noise from a wheel on an ex my knee jerk response is "check the wheel bearings" >.<

[jakedrew]

I had my rear diff make noise at 55k miles. I get up to about 55 mph and you could hear a humming, let off the gas it goes away, give it a little gas and you could hear it.

Took it in (Extended warranty) and they couldnt hear it, but I told them I only hear it after about 10 miles/ fluid gets warmed up. So i took it up and down the freeway and had a tech come with me for a ride and whaa laa rear end making noise.

All better now.

It was a 1100$ job at ford, but i had a 100$ deductable so i got lucky. they put in a new ring and pinion and change to thicker fluid.

Good luck.

[gbranh]

Turned out to be rear passenger side hub bearing. Had it fixed, good as new!

Greg

[hoss_hanna]

so my knee jerk was right? lol

[gbranh]

Indeed it was! Thanks for the advice!

Greg

[thepotroast]

Originally Posted by gbranh

Turned out to be rear passenger side hub bearing. Had it fixed, good as new!

Greg

Exactly as I had predicted in my initial response

[Juandedios74]

Hello All,
Nubie here and I also have an 02 Explorer XLS with 99,318K on it. Everything still factory on it and it too has developed several issues which I have worked on lil by lil to get all the lights off of the panel. My Explorer also makes the humming sound towards the rear of the truck once it reaches a certain speed. Yesterday after a trip 200 mile trip I parked the truck in my garage and noticed that the rear differential was lieaking oil from the bottom of the diff and alos noticed that the truck is making a jerking or stuttering I let off on the gas. I've read the post on this string and was wondering if anyone has an idea on how to repair/replace any of the kits on this truck. Pictures would be great as I'll work on it with my laptop next to me. Any help would be appreciated.

[DVRDOWN]

Originally Posted by gbranh

Turned out to be rear passenger side hub bearing. Had it fixed, good as new!

Greg

Gbranh, did you replace the bearing yourself or have a mechanic do it? If you had it done, what did the job run you? I will be replacing my 4th, yes 4th, right rear bearing on my '02, as well as the left rear and really don't want to tackle the job myself in south florida heat.

[Gaff It]

Gone through the rear diff hum now. Just had a rear axle seal replaced. Soon after, I hear the hum. Plan to take it back to make sure they put enough oil in after the seal replacement. If so, how long do I have before I am faced with a $1500 repair bill. Have 80,000 on the Ex now. It is great shape otherwise.

[CFieldAZ]

any after market rear diff brands recommended?