What's that sound?

[Elessar65]

OP's signature indicates a 98 4wd with a manual trans. So that makes it an M5OD-R1 with a 4405 TC (I think?), so if that is the vehicle in question then he has 4auto-4hi-4lo. Auto uses PWM with the TC clutch to vary the amount of torque to the front wheels.

 

[J5hort]

I have chased sounds around on both my Gen 2 and Gen 4 Explorers. Humming at certain speeds, knocks on floorboards when driving, grinding when turning. Even was convinced that there was a problem with front left CV and axel shaft when it was actually a problem with right rear hub. More often that not it was a worn hub that was the problem. If they are the originals, they probably should be replaced. Do a quick test on all 4 wheels by trying to move tire with your hands at 12 and 6 o'clock. You may also want to try using a mechanics stethoscope near each hub as you rotate wheel.

Regarding hubs. I have replaced both front and rears for several Explorers many times. Not a trival job to replace, most of it is labor so expansive if you have someone do it, front hubs are bolt on, but rears have bearing that needs to be pressed on. Use Moog or Timken or you will be replacing again in 6 months.

 

[grizzlyxjim]

I used to have a Suzuki Samurai that made that same sound when the oversized tires rubbed on the homemade fender flares.

 

[Mitchs07explorer]

I’m betting on a hub being bad especially when you say you slow down and the noise slows too. That is much harder to determine when your accelerating. I replaced both from hubs on my gen 4 and I have the 4x4auto, 4hi, 4lo option. There was zero movement when I tried to move the wheel around even when the sound got really bad. It was most noticeable between 30-40 mph. I took it to a shop to have them listen for it when I first suspected it but they couldn’t determine what the noise was. Then several months later I went back and it was much more obvious when we spun the wheel, we could hear it lightly grinding. Take it to a tire shop and have them listen to it, they probably need to take it for a longer test drive versus just around the block. I had to drive it fit the better part of a year before we could determine it was the hub. Also not sure if your vehicle had this but check the abs toner ring as well and make sure it’s not damaged, the rock could have hit it throwing it off. The hubs are really easy to change because they are sealed units and you can do it for a hell of a lot less than the shop will charge you. Good luck

 

[E.T.]

I’m betting on a hub being bad especially when you say you slow down and the noise slows too. That is much harder to determine when your accelerating. I replaced both from hubs on my gen 4 and I have the 4x4auto, 4hi, 4lo option. There was zero movement when I tried to move the wheel around even when the sound got really bad. It was most noticeable between 30-40 mph. I took it to a shop to have them listen for it when I first suspected it but they couldn’t determine what the noise was. Then several months later I went back and it was much more obvious when we spun the wheel, we could hear it lightly grinding. Take it to a tire shop and have them listen to it, they probably need to take it for a longer test drive versus just around the block. I had to drive it fit the better part of a year before we could determine it was the hub. Also not sure if your vehicle had this but check the abs toner ring as well and make sure it’s not damaged, the rock could have hit it throwing it off. The hubs are really easy to change because they are sealed units and you can do it for a hell of a lot less than the shop will charge you. Good luck

Easier if you switch the whole knuckle. Slide hammering out the old hubs is a PAIN:



although with an older model I think you might have smaller knuckles. I did my front right and have the knuckle for my front left sitting in the truck waiting to see how bad the old one will get.

Your noise has the exact same frequency as driving on the markings at the edge of the road, which is.. bizarre. When my hubs (which is to say bearings) went they weren't intermittent at all

 

[Uncle Jimi]

Let's play "What's! That! Sound?!"

I started hearing this sound after a camping trip this past summer. I recall driving over / kicking out a small rock while parking on gravel.

Vehicle:1999 Ford Explorer OHV 5-Speed Manual with ~103k miles

The situation: It is a rapid-fire, machine gun growling sound coming from the front of the vehicle. It can be felt through the floorboards at times. Sometimes it lasts less than 1 second, other times it spans up to 3 seconds. This sound happens only while the vehicle is moving. It happens at any speed, but typically occurs while moving through 30 mph. It occurs in gear, in neutral, in gear - clutch depressed, and while braking. It can occur on smooth pavement, or sometimes is triggered by a bump in the road.

I put together a compilation of the sound from this morning's drive: If the link doesn't work, please tell me and I'll upload to youtube and repost the link.
https://photos.app.goo.gl/XruAyhro15ZvRcg48

What I've done so far: When this sound initially occurred, the ABS light came on. I took it to the mechanic and they diagnosed a bad rear speed sensor, but was unable to replicate the noise. I replaced the rear speed sensor myself. Later, I replaced the both front speed sensors while doing the front brakes. Issue is still occurring.

I'm not opposed to taking to the mechanic, but I'd like to be able to point them in the right direction. Don't want another "unable to replicate problem" diagnostic that I have to pay for.

Thoughts?

Thank you!

Tire noise? You may have a bubble/blister in a tire after doing the gravel road. Is it only at one speed and if not is it more rapid at faster speeds? Tire problems can be impossible to find. put on your spare, one corner at a time to check. Do you have a set of spares? Good luck, I hope you don't have to search too long. JW

 

[TsherryUSA]

I’m betting on a hub being bad especially when you say you slow down and the noise slows too. That is much harder to determine when your accelerating. I replaced both from hubs on my gen 4 and I have the 4x4auto, 4hi, 4lo option. There was zero movement when I tried to move the wheel around even when the sound got really bad. It was most noticeable between 30-40 mph. I took it to a shop to have them listen for it when I first suspected it but they couldn’t determine what the noise was. Then several months later I went back and it was much more obvious when we spun the wheel, we could hear it lightly grinding. Take it to a tire shop and have them listen to it, they probably need to take it for a longer test drive versus just around the block. I had to drive it fit the better part of a year before we could determine it was the hub. Also not sure if your vehicle had this but check the abs toner ring as well and make sure it’s not damaged, the rock could have hit it throwing it off. The hubs are really easy to change because they are sealed units and you can do it for a hell of a lot less than the shop will charge you. Good luck

Yeah, my gut was telling me it was the hubs. I'll be rotating the tires this weekend, so will do a spin and listen when I have it up.

Thanks for all the input everyone. Getting the mind-hive second opinions has really helped. I haven't done a hub change before and I don't have my Chilton manual with me right now, but I'll check out some Youtube videos before giving that a go. Anyone have a recommendation of MOOG vs Duralast? Also looks like I'll need new mounting bolts and axle nut. Doesn't look like Autozone carries the axle nut. Any recommendations on where to get that part?

 

[TsherryUSA]

Tire noise? You may have a bubble/blister in a tire after doing the gravel road. Is it only at one speed and if not is it more rapid at faster speeds? Tire problems can be impossible to find. put on your spare, one corner at a time to check. Do you have a set of spares? Good luck, I hope you don't have to search too long. JW

Tires are pretty new, but will do an inspection this weekend when rotating.

 

[Uncle Jimi]

Tires are pretty new, but will do an inspection this weekend when rotating.

You'll have swap em out one at a time but if you can't see if it moves when you rotate. You probably won't be able to see the problem. Having the sound start after, (a) new tires and (b) after a gravel road/parking lot experience would make me swap tires to check if you truly care. I've had a tire shake problem that no one could find, I got the car because no one, not tire shops, not mechanics, not laymen, not even me, could find the problem until I decided to put different tires on it and resell it, Then it drove fine for another 50,000 miles; The previous owner changed axels and brakes and his mechanic wanted to try the transaxle. I've had your problem a couple of times but worse, one leaked after a few days and one annoyed me until I changed the tire. I've driven on dirt/gravel roads, logging roads, and ranch road all my life and although it's not common for new tries to separate and make that noise it happens. That tire could start to leak fairly quickly at speed, or parked, anytime. Let me know if you find it. I'd bet.

 

[gsimon767]

Let's play "What's! That! Sound?!"

I started hearing this sound after a camping trip this past summer. I recall driving over / kicking out a small rock while parking on gravel.

Vehicle:1999 Ford Explorer OHV 5-Speed Manual with ~103k miles

The situation: It is a rapid-fire, machine gun growling sound coming from the front of the vehicle. It can be felt through the floorboards at times. Sometimes it lasts less than 1 second, other times it spans up to 3 seconds. This sound happens only while the vehicle is moving. It happens at any speed, but typically occurs while moving through 30 mph. It occurs in gear, in neutral, in gear - clutch depressed, and while braking. It can occur on smooth pavement, or sometimes is triggered by a bump in the road.

I put together a compilation of the sound from this morning's drive: If the link doesn't work, please tell me and I'll upload to youtube and repost the link.
https://photos.app.goo.gl/XruAyhro15ZvRcg48

What I've done so far: When this sound initially occurred, the ABS light came on. I took it to the mechanic and they diagnosed a bad rear speed sensor, but was unable to replicate the noise. I replaced the rear speed sensor myself. Later, I replaced the both front speed sensors while doing the front brakes. Issue is still occurring.

I'm not opposed to taking to the mechanic, but I'd like to be able to point them in the right direction. Don't want another "unable to replicate problem" diagnostic that I have to pay for.

Thoughts?

Thank you!

I am sure it is the front sway bar bushings. Had the exact same issue. Almost sounds like a machine gun or loud flutter usually while slowing down. Replace the sway bar bushings and links while you’re at it. Cheap fix.

 

[J_C]

I haven't done a hub change before and I don't have my Chilton manual with me right now, but I'll check out some Youtube videos before giving that a go. Anyone have a recommendation of MOOG vs Duralast? Also looks like I'll need new mounting bolts and axle nut. Doesn't look like Autozone carries the axle nut. Any recommendations on where to get that part?

This is a pretty straight forward repair, a manual is not really necessary for the order of disassembly though it is good to find the torque specs for fasteners, and especially have a torque wrench to put the axle nut back to the right torque or else it can wear out the new hub/bearing prematurely. Torque the axle nut to final torque with the vehicle down, wheel on, vehicle weight on that wheel.

Bolts, I would reuse and well as the axle nut unless they are really bad. You'll have to take a look and it can vary. I have a fair amount of rust under my '98 but for some reason the axle/nuts area has not rusted much, and they are the originals.

Some will say you should get a new nut. Okay, they can do that and you can too, but I just reuse mine if in good condition.

Otherwise you just take the brake caliper bracket off, beat the axle a little with a center punch or on the nut while installed on the axle (to avoid damaging the end edges of the axle stud) to break it free of the hub (penetrant spray for this and all fasteners ahead of time is a good idea), unbolt the hub, and beat/pry/whatever it out of the knuckle. Again, penetrant spray may help if rusted in.

Clean off the rust on any area where two pieces mount back together including fastener seating points and reinstall. Remember to unplug the ABS sensor from the knuckle and nearby frame mount location before pulling it off.

I prefer the Timken SP450200 hubs on Rock Auto. They are a major brand and very reasonably priced at about $95, though "right now" Rock Auto has one as a closeout for $63.

1999 FORD EXPLORER 4.0L V6 SOHC Wheel Bearing & Hub Assembly | RockAuto

The axle nut, try a ford dealer in town or online, or ebay, etc (search this part #) IIRC (check for yourself to be sure) the part # is N808985-S100. Torque for that is 157 to 213 ft-lbs. 32mm nut.

Hub bolt torque is 74-96 ft-lbs, brake caliper bracket 72-97 ft-lbs. It is recommended to use threadlock compound on the bracket bolts as many have had them come loose over time.

 

[J5hort]

Having done this many times and also being a regular Autozone shopper, I can only recommend Timken or Moog hubs. I usually shop Duralst and others for my parts and in most cases it is not a problem, but my experience has been, given the amount of labor to do the wheel hub replacement, a quality part makes a big difference. I have learned the hard way with the only positive side is the experience I have gained.

 

[Uncle Jimi]

I am sure it is the front sway bar bushings. Had the exact same issue. Almost sounds like a machine gun or loud flutter usually while slowing down. Replace the sway bar bushings and links while you’re at it. Cheap fix.

Sway bar bushings usually make a sharper sound and can be correlated to bumps but if a tire is out of balance or bearings are bad it may be the issue; it's certainly worth checking.

 

[Justinwht]

Have two '95 (auto) and a 2000 5-speed. Manual says to use 4WD only on sand, snow, dirt (something like that) because the front wheels are locked (unlike rear-end differential driven wheels). The sand, etc allows the wheel to jump or skip on sharp turns.

 

[toypaseo]

I have Timken on one front, and Precision on the other. @Turdle recommended the Precision brand to me.

 

[toypaseo]

Have you ruled out the exhaust hitting underneath?

 

[2001SportOwner]

Could you have a bad catalytic all broken inside rattling under acceleration ? im guessing a front cat broken up

 

[rustylugnut]

Exhaust is suspect, didn't think of that. I could believe a sway bar link as well.
I believe Timken is the OEM supplier for the wheel bearings. I have one on the driver's rear of my mountaineer. No issues with it after 5,000 miles. But this really doesn't seem like a wheel bearing. A wheel bearing would have given many obvious symptoms of being worn before getting to this point. Any grinding or other strange wailing or howling noises at speed?

 

[fast_dave]

Tire noise? You may have a bubble/blister in a tire after doing the gravel road. Is it only at one speed and if not is it more rapid at faster speeds? Tire problems can be impossible to find. put on your spare, one corner at a time to check. Do you have a set of spares? Good luck, I hope you don't have to search too long. JW

@Uncle Jimi

I was thinking it's bad tire as well, and if you regularly rotated your tires and the noise moved with the rotation - well, you get the point

 

[toypaseo]

I think I would count out front wheel bearings. When I had a bad one, it would howl on the highway, and be quiet when turning.

Other things to look at: engine mounts, transmission mount, and the three front differential -axle housing mount bushings...