So, my fiance purchased this new off the floor before i met her (or else she wouldnt have bought it lol). Had a motor issue which required a new motor after 90k miles.. Anyways, while driving on a normal road, i dropped the rear window and hear this whining noise. Checked the transmission fluid and it was a little low, nothing major. Topped it off with Mercon V... No effect. Where do i look next. It does not have a tow package. Do i check the transfer case, or rear differential?. Im torn.. Im thinking differential because the transfer case is more upfront to where the noise is. you cant hear it with front windows down. Only the rear sliding window or rear passenger's windows.

If anyone has any other suggestion or anything, id be very greatful
thanks

 

first thought would be wheel bearing or pinion bearing. Look for oil leakage at wheel ends on inside of tire, brake drum... jack up rear and try to pry tire up and down... rotate and listen for noise... etc ............. crawl under truck and move rear end of drive shaft up and down , see if pinion moves or wiggles ?

 

First, thank you. I know i asked only about the transfer case and differential. I appreciate that you gave me other things to look at/for. I should put that in my 1st post.
Ok... So no leaks at the wheel ends nor brake drums. As for moving tire up and down and wiggling it, nothing.

The thing i can relate to the sound is that of running on off-road or studed tires. And, im sorry. Its not so much a whine but a constant hum.. Could this be the "infamous" explorer rear end noise but in the sport trac.
Tomorrow im going to check and most likely change the differential oil.

 

changing the oil sure cant hurt.. The explorer noise you mention was in the IRS axles, but your right, the pinion bearing was one cause of the noise. Maybe the condition of the oil will help determine the problem. Brearing noise is normally the result of dirty oil and wear on the bearing race. You may see steel "dust" or slivers in the oil... It could also be similar wear on either wheel bearing. Initial scoring of the race will cause "noise", but enough damage is not present to give excessive clearance at this point.

 

Your right, these axle problems with "noise" are very difficult to pin point....... Eventually when the noise gets bad enough you just have to break down, jump in , and look.

 

same noise, but the "OTHER" axle..... Yours is not IRS, but probably the same 8.8 size parts internally. This just gives you an idea of location of noise.

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

 

Steve,

Again thank you for your information. The noise is definitely as if riding on new off-road tires, studded tires or even running in the rumble strip minus the vibration and not as loud.

I have posted this issue on a couple of sites, and got this for a reply.

Any thoughts?

Ive got rain scheduled for day or so...So im still looking over all suggestions from replies and online.. But id like your opinion on the above reply i recieved.. I can answer that the noise is only while in motion, any speed. I wven dropped to neutral down a hill, no effect.

Thanks

 

in neutral, coasting down a hill.... still noise. That is probably a bearing. Normally a pinion bearing will change tone when loader or unloaded. Coasting or under power, the outboard wheel bearings ( end of axle) really don't know the difference. You could try the jack and block method and see if it changes. You can set right by the tire and listen at least and see what you can hear... It might work ......... as I said, axles are hard to trouble shoot and pin point.. Often you wait till its TOO NOISEY" and do the overhaul ........... but since your noise is constant even when coasting, it may be outboard bearing.

 

I hate to say it, but I would double check the front end also.... Lot more common for the hub/ bearing on the front of 4 x 4 to go bad than to have a rear axle problem. ....... same test, jack up a tire and rotate it and listen / feel for stiffness. Compare left to right sides........ I have had to take the brake shoes off to get a better "FEEL" for the front end bearing / hub problems.... remember, these bearings are sealed and never get additional lube, where the back are constantly flooded.

 

Another thing to do is jack up both sides of the rear axle and spin a tire.....do you hear/feel anything? Could be worn spider gears. I attributed what I thought was a bad bearing on bad spiders in my Astro van. Spun the hub on either side and one side was louder than the other, so I replaced the wheel bearings ( which still appeared fine with 225k on them ) only to discover the noise was still there....then I actually looked at the rear end gears and saw the wear on the spiders. Ultimately a fairly easy and cheap job to do, considering what it would have cost me if the spiders had actually eaten themselves up and spread chunks of metal everywhere....