Droning, humming sound from truck.

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  #1  
Old 09-20-13, 10:53 AM
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Droning, humming sound from truck.

I have a 92' Ford Ranger XLT with 2.9 V6. I have a droning, humming sound when accelerating, decelerating, and coasting. It is sort of like an off-road tire sound from underneath the truck. Is this driveshaft/differential related? The pitch rises and falls respectively with increase or decrease in speed.
 
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  #2  
Old 09-20-13, 04:42 PM
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I would jack up the drive wheels and run it. If the noise is gone it is probably tire related. If it is still there maybe you can tell where it is located. This is a start anyhow.
 
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Old 09-20-13, 05:19 PM
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Yeah, I was thinking about doing that this weekend. Silly question. But any precautions when I do this procedure? Do you mean put jackstands under the axle so both tires are off the ground? Couldn't it tip over and get hung up on a jackstand?
 
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Old 09-20-13, 05:53 PM
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How many miles on the vehicle ?

Being a Ford man and hearing that on my vehicles....it's the differential.

While you are driving..... hold the throttle at the break even point..... not accelerating and not slowing down....does it come and go ? If yes then it's definitely the differential.
 
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Old 09-20-13, 06:59 PM
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Possibly a wheel bearing.
 
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Old 09-23-13, 11:02 AM
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It has over 330,000 miles. The front bearings were recently repacked and the rear bearings are not leaking gear oil. The center bearing in the middle of the drive shaft is badly worn. Not just the rubber insulator but looks worn all the way through. Could this cause it?

I had a pinion seal leak. But differential didn't go dry and I had it fixed early. I have also topped off and replaced rear axle gear oil 6 or 7 times.

I just did test recommended by PJmax, and the sound did not come and go.
 

Last edited by bluesbreaker; 09-23-13 at 11:47 AM.
  #7  
Old 09-23-13, 01:27 PM
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Take a close look at that driveshaft bearing, Ive seen them mimic a pinion brg noise. That goes back to jacking it up and listening. And no if it is on jack stands it wont tip over.
 
  #8  
Old 09-23-13, 01:53 PM
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I just finished listening with rear tires raised off ground and engaged in drive. I could hear the noise. But I couldn't tell for sure what part of the drive line it was coming from. It seems to be loudest between area of pinion bearing and center bearing.

I also noticed that both U-joints (with grease fittings) are slinging grease on the under body of the truck. Don't know if this is normal.
 

Last edited by bluesbreaker; 09-23-13 at 02:36 PM.
  #9  
Old 09-23-13, 05:39 PM
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Somebody probably over greased the u-joints,nothing you can do about it now. Take a peice of broom handle or a long screwdriver and put one end on the brng. carrier then on the diff hsng while pressing the other end to your ear. Should be able to tell something. Yes sounds will travel in a drive line.
 
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Old 09-23-13, 05:46 PM
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I just did test recommended by PJmax, and the sound did not come and go.
I am surprised. My current Ford vehicle.... a 99 E-350 diesel super cargo van has 350K miles on it and it sings like a bird. Quiet during acceleration..... loud hum/whine you take your foot of the gas.

Very common on older Fords. All my trucks have down it to some extent.

Just a case of the ring and pinion not knowing the words.
 
  #11  
Old 09-23-13, 06:48 PM
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I have been greasing the U-joints myself. I was told that you keep pumping in grease till some squeezes out through the seals. So I guess I am the one over greasing if I am doing it incorrectly.

That center bearing doesn't have a grease fitting. So that means if just has internal sealed lubricant, correct? It is the original part since 1992.

I don't have a long enough screwdriver. I have a broom stick. But would a metal yardstick, PVC pipe, or hollow galvanized steel pipe work better?
 
  #12  
Old 09-23-13, 08:09 PM
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Ya when you lube a u-joint you just want to "fill" it. When you over do it you can damage the seals. You can use anything as a makeshift stethescope.
 
  #13  
Old 09-25-13, 08:00 PM
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This afternoon I had the mechanic test drive the truck. He also had me listen with a stethoscope. He wrote me an estimate for about $1100.00. This would include ring and pinion, diff kit seals and bearings, axle bearings and seals, labor, supplies, and tax. Of course, I'm getting a second opinion.

But if I really need all this, is this a fair price? Is there a way I can reduce the cost, like buying my own discounted parts? What about buying an already assembled differential instead of him rebuilding?
 
  #14  
Old 09-26-13, 06:01 AM
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If you buy your own parts you better be able to install them yourself. When running a shop you need the markup on the parts to cover your overhead,so the labor can go to buying shoes for the kids.
 
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Old 09-26-13, 08:03 AM
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I hear ya.' But buying shoes for the kids applies to all of us
 
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