Whir Whir Whir Whir Whir, But nothing is wrong!?

[DeerSlayer]

I have had a noise from my read end that has steady gotten worse since Jun this year (9,000 miles). It is a constant whirring noise that is speed dependent. Starts being loud at about 25 mph and gets louder by 65 mph then gets drowned by road noise. It stays the same with braking and it is the same at any RPM. I just got it out of a trustworthy shoouldn't find anything wrong. They heard the noise and told me it wasn't worth looking into. I disagree. They did put a listening device and use a stethoscope on every bearing on the rear end (Axles and diff). They said everything sounded very good, very quiet. The fluid level in the diff was good and there wasn't any metal shavings. They checked the play in the diff bearings and everything was good. The one thing they found was that the axle had a little slack before it began to turn the ring gear. Could this be the problem? Anybody else have this problem/noise? Thanks for any help.

 

[Dan Whitaker]

Check your tires! A cupped tire will cuse what you are describing. Bad shocks will cause this.

The reason for the noise is because when the tire cups it traps air between it and the road surface.

The faster your speed the more times the cupped spots contact the pavement.

Think of it as clapping your hands.

 

[marragtop]

I agree with the tire possibility. If you can, get both rear wheels off the ground and put it in gear. If the noise is not there, then it could be tire or some 'load' related issue. Needless to say, don't have it in 4wd when trying this.

 

[DeerSlayer]

The shop couldn't locate the noise with it on the lift. I will look into the tires. What causes cupped Tires? Over inflation? I run at 32-35 PSI. Is that to high? Thanks alot!

 

[mgmgmg]

I have the same problem! My winter 94 Ltd. with 245k... Its the bearings in your rear end....Theres 4-5 bearing...the sound is comong from one of those bearings.. reason I know that my buddy works as a mechnic for ford....Its very expensive to get those replaced....600$-800$ Ive been riding with this problem for years now...but I only put on 3-4k a year its my winter SuV...

 

[savagefan]

Does the noise go away when you lift your foot off the gas pedal? if so, pinion depth is an issue and can be caused by something as simple as a loose pinion nut.

 

[DeerSlayer]

I am pretty convinced that it is not bearings. The shop I bring it to has been reliable to my family for more than 15 years. They road tested and heard the noise, listened to each bearing with a stethoscope and microphones on the lift and said that each bearing sounder either perfect or near perfect. No one bearing stood out.

The noise USED to be more prevalent when I took my foot off the pedal, but mostly because the engine RPMs died down. It has gotten louder now.

I have free tire rotations and inspections at Les Schwab, I'm going to try that tomorrow. If they say the tires are all right and the noise stays that I am going to bring it to a rear end specialist. Anybody know a good one in W. Washington? I've heard Randy's Rack N' Pinion is good.

Thanks again for the ideas!

 

[DeerSlayer]

Took it to Les Schwab for a rotate and balance they said there was 75% tread left and that there was slight cupping on the front tires. They also said that this is common on these explorers even with new shocks (Mine are 2 years old) because they have a bouncy ride. The tire rotation should lessen the cupping according to LS. I'll update in a few hundred miles to see if there is any change, as there was no immediate result after rotation and balance.

 

[Tony H]

I'm betting on the inner Pinion bearing.

 

[mgmgmg]

Heres the deal if u let go of the pedal and noise goes away...try driving at 25-30 mph and see...if so its your rear bearings 100%...

 

[mgmgmg]

Does the noise go away when you lift your foot off the gas pedal? if so, pinion depth is an issue and can be caused by something as simple as a loose pinion nut.

This loose pinion depth....do i need take off pumkin cover off to view? Sound very simple....Could you explain more

 

[savagefan]

It's the big lock nut that holds on the companion flange. Get under neath and see if you can move the rar u-joint assembly up and down, this would indicate a loose nut. If so drop drive shaft, buy a new lock nut and torque to spec.

 

[Bryce_james]

Check your brakes I had I leaking rear celluloid it made my brakes stick and I had to have my drums turned. New brakes and caliper and i was good to go!

93' Exp. From Heck!
-Bryce

 

[mgmgmg]

Yeah went under the suv to check if u-joint was loose....tried to move it up or down...Its soild.....The u-joint isnt loose or will not move....So I quessing its not the u-joint?

 

[sasqwatsch]

Constant deep pitched GROWL

Following a complete brake job, my '91 2WD Explorer (100,000 miles) developed a deep pitched constant growl. It's not a squeak, hum, or whir - almost sounds like large metal pieces turning without lubrication. SEEMS to be coming from the drivers side rear. Volume level not affected by RPM - loud at any speed, doesn't change when gearing up or down or in neutral at any speed. Differential was a pint low, added oil - didn't change anything. Goes away only when not in motion. PROBABLY UNRELATED BUT... once in awhile, put the key in the ignition and it just clicks - my wife pops the hood, wiggles the battery cables, and it fires right up. Doesn't happen on any regular basis. Cables are clean and tight. Wife says volt gauge reads above normal for awhile after this happens. Headlights don't fluctuate with RPM's. Any clues where I can start looking?

 

[Bryce_james]

There is a Caliper, Some call it a Brake celluloid that spreads the rear brake pads, if that leaks your brake pads get shot fast and they will start to stick to the drums and not release. you will tell if it has been leaking if you see brake fluid behind the brake pads. Replace the Celluloid and pad and if your drums are ok then clean them good, new pad and you should be good to got again.

If not this check you barrings!

 

[DeerSlayer]

So after about 500 miles after the tire rotation and balance the noise is slowly fading away. I guess it was tire cupping. I want to test it again on a smooth gravel road and see if I can hear the noise. It seams that on gravel the cupping would be unnoticeable. If I can even hear a glimmer of the noise then I will know that it is something else besides tires.

Thanks for the Suggestions.