My awd 4.0 v6 Explorer XLT has been making a "howling" noise that is getting louder over past few months.
Sounds an AWFUL lot like a wheel hub, but I just replaced left front and don't think it is that anymore.
That didn't fix it any ways.
New tires last week, that didn't fix it or change it.
I drove around for a couple months w/o front driveshaft before that and same noise.
Being in awd auto or engaging front end, no change.
Most prevalent 65 to 85 mph.
Can hear it starting about 45 and once over 85 seems to get quiet again.
Does seem to be coming from under my feet as I drive area.
Sound changes with wheel speed not engine rpm.
Wondering if it might be transmission or transfer case related now...
I remember checking lube in front differential when I purchased this Explorer a while ago.
And if I remember right transfer case too.
Would like to check transmission fluid, but....
Not like pulling a dipstick on this one.
Wondering if anyone with greater knowledge than my own (not hard too surpass that, trust me ) has any ideas or if there are common issues with these transmissions, transfer cases, or awd set ups???
When I installed the front hub last weekend I noticed cv joint had what looked like a hole in it that someone had put a dab of sealer on.
I never saw any grease flung around, so I was curious if that may have been an issue.
I took a syringe tip on the end of my grease gun and felt like I nearly filled the entire boot up and sealed and taped the boot up to contain the new grease in there.
No mess yet, but my hopes of quieting the noise down by adding lube to what I thought may have been a dry neglected cv joint didn't happen either.
When I had the front shaft out I checked front u-joint and it seemed fine.
I also took apart the cv by the transfer case (not intentionally) but did pack full of grease and lube that up too.
But like I said same noise/howl in AWD or not, with or without driveshaft same too.
Hate to replace anything more unneeded.
Appreciate any help, ideas, or thoughts ! ! !
Thanks ! ! !

 

You seem to have focused most of your time on the front end. Is there something about the noise that makes you believe it's in the front? Your general description of the noise sounds very similar to the very common noise that most attribute to pinion gear noise in the rear end.

You might try changing out your differential oil to see if that at least changes the noise or has no effect. If it's in the rear end, changing the oil should at least make some difference. It may not cause the noise to go away completely but it also would not be a waste of money.

-Rod

 

When driving from the "cabin" it seems to be coming from the left front, that is what has me focused there.
A few days ago I rode in passenger seat front and I did not hear it as much.
Haven't rode in the back, but will see if I can check out the rear differential and look there further after hearing this.
I know I checked the gear lube level a while ago, but I will see about changing it out now knowing that is something that happens often.
BIG THANKS !!!

 

https://www.ford-trucks.com/forums/1...e-rebuild.html

 

THANKS for that too.
HOPING I won't need it, but if the time comes I will have that resource.
Appreciate it

 

It sure sounds like it is coming from under my feet while I drive.
Planning to try and change gear lube in both differentials when I am able...
Unfortunately and I hate to admit that it will probably be a couple weeks before I get to it.
But I had son drive so I could try to judge from other spots inside the Explorer.
Can hardly hear anything in any other position besides driver's seat.
Going to try and make sure it's not the rear pinion after hearing all this about it being so common, but I guess I will ask a couple more things.
1st, anything special for gear lube,or anything better than just 85 W 90?
Additives?
2nd, how about the transmission or transfer cases?
Any known issues there for noises?
I know I see a lot of these Explorers with bad transmissions, usually hear about slipping not noises.
The AWD transfer cases?
And...
How about a CV axle?
I know I used to be able to tel a bad one by hearing clicks and clunks while turning or accelerating?
Wondering about the axle on driver's side...?
There is a slight difference in noise when turning slightly at highway speeds.
Like when changing lanes at 80 mph, tone changes a little.
Acceleration decelerating seems same.
I almost would expect pinion bearing to be effected like a joint when it's bad....
Again THANKS for any thoughts or advice !!!

 

Make sure you can get the fill plugs loose for the differentials (and transfer case) before you drain them.

There is an additive that Ford calls out for the rear differential. I'm not sure I still have the info, but you can probably find it on this forum or the Internet easily enough.

One version of the 4WD transfer case seemed to have an issue with popping and making noise, but if you have AWD I don't recall hearing of issues with them unless you often run different tire inflations or mis-matched tires.

A worn CV joint could cause noise, but I don't expect you'd only hear noises from a bad joint at highway speeds versus low speed sharper turns and/or acceleration.

-Rod

 

Kind of what I thought and was thinking too.
Just seems to be coming from that front/left quarter of the truck.
I will do the differentials and try to come up with anymore scenarios until then.
I did have the driveshaft out up until a couple weeks ago because I had mismatched tires.
I drove a few miles like that and could tell it wasn't good for the AWD.
The noise/hum started while I was in "2wd" mode.
I was waiting until new set of tires and driveshaft installed to see what happened.
But just seems like the more miles I drive the more noticeable.

THANKS again !!

 

Wondering if there was any chance anyone had any luck with any type of "miracle cure" for the differentials?
Anything like adding Lucas treatment to the gear lube help?
Thought I would check prior to filling full of fresh lube.
Still probably a few weeks out, but thought I'd ask if anyone had noticeable results beforehand.

 

I did have the driveshaft out up until a couple weeks ago because I had mismatched tires.
I drove a few miles like that and could tell it wasn't good for the AWD.
The noise/hum started while I was in "2wd" mode.---------

Are you saying the noise FIRST STARTED when you drove with the front shaft out ?/ On an ALL WHEEL DRIVE, I don't think that is a good idea.. I believe the transmission has to see the front wheels turning as it is comparing wheels speeds to determine when to engage the front end.... this could be a BIG problem.

 

Read the bottom post

https://www.ford-trucks.com/forums/1...t-isusses.html

 

Ouch ! ! !
Wow I hope that isn't the case and I didn't wreck anything.
Noise I am hearing now had started before I removed the front shaft.
It has just been getting more noticeable all along.
I had a tire just fall apart a few months ago and bought a used set.
Even though they were labeled same size could tell there was some binding when I drove.
Tried to over inflate the smaller pair and under inflate the tall ones but still scary sounding and binding feeling.
Pulled the front shaft until I got a new set of four.
Put shaft back in after tires were installed.
It drove OK without, about same noise initially as it had with shaft and matching tires.
Got a little more noticeable as I drove w/o.
I kept thinking it was front hub because it sure sounded like that.
I waited until I had new tires and shaft back in to see if any different.
Still seemed to be there at first and then more and more noticeable since.
Past week it has felt and sounded more like what I would think is rear u-joint.
Maybe in my head after hearing all the pinion info.
But when decelerating from 85 to 80 mph it reminds me of u-joint now.
Man, have my fingers crossed now that I didn't do too much damage.
I have to do some digging soon.
Most of this weekend is going to be my Bronco and lawn tractors.
Will get at my Explorer as soon as I can.
Appreciate letting me know the info and link....like I said "fingers crossed"
Will definitely no better next time if there is one.

 

Please confirm if this is an AWD Explorer or a 4WD Explorer. In post #8 you also mentioned "2WD mode" but I'm not sure if you were referring to forcing 2WD by removing the front driveshaft or if by pressing a physical switch. If you have a switch for 2WD it is not an AWD model.

-Rod

 

Oops, sorry.
It is in fact AWD.
It has buttons for AWD Auto, AWD, HI, and AWD lo.
I was referring to time w/o front shaft as being 2wd.
Thanks for catching my poor choice of words.

 

Still didn't get it all quite right....
4x4 Auto
4x4 High
or
4x4 Low