Howling on acceleration

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Aug 3, 2004 | 08:28 PM

aerostargal

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From: Ohio

Howling on acceleration

Hi All,

Our 97 F150 SC 4x4 4.6L V8 has a weird "howling" sound only on acceleration. It stops as soon as we let off the gas.

This truck has 140K on the clock and the howling started around 137K. We have no history on it since we purchased it from an auction resaler in November 2003.

Just had it in to our mechanic who said the differential had no fluid at all. He fixed it up (additive and all), but we still get that howling sound.

What the heck causes that noise? Any advice or insight would be greatly appreciated!

TIA
aerostargal

Aug 3, 2004 | 08:37 PM

Racerguy

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Joined: Aug 2002

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From: BC, Canada

You probably have bad pinion bearings. I've replaced quite a few of these for the same problem. Unfortunately it usually means pretty much overhauling the whole rear diff.

Aug 3, 2004 | 10:32 PM

Bikeitswift

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Joined: Mar 2003

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From: Canyon Lake Texas

Mine's a whine...

I just picked up an early 97 F150 2WD with 26,400 miles on it (little old man's truck!). I have the back seay reat removed to do some quarter panel body work, and because of that I can really hear the road noise through the cabin vents that open up when the AC is taken of "Max" and put on another setting. When doing so, I hear a high pitched whine when accelerating or under load...faint, but seems louder after the truck is driven about 40 miles or so. I assumed this was coming from the transmission, but might it be the pinion bearings as well?? Sure not many miles for that sort of stuff to happen...but if its my transmission (auto OD), what;s up with that? b After 100 miles, I can clearly hear it when I have the windows down in town and take off from a stop.

Aug 4, 2004 | 12:26 AM

Racerguy

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From: BC, Canada

I've seen some with low miles have bad bearings too.
Usually the noise will be there either under acceleration or deccel but not both if its the bearings.
At low speed when taking off the noise you hear is probably planetary gear noise in the transmission and is nothing to worry about unless it gets really loud.

Aug 4, 2004 | 08:19 AM

aerostargal

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From: Ohio

Thanks Racerguy. Any idea how much it might cost to have the rear diff overhauled? The service center we take our trucks to charges $58/hr labor and a minimal mark-up on parts.

Aug 4, 2004 | 08:38 AM

Racerguy

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From: BC, Canada

No, I dont know how much it would cost. I dont normally see the prices on most jobs...I just do the work

And I'm in Canada so our prices will be different.
I would get your mechanic to check and see what it needs and get a quote. You might want to get a couple quotes to make sure it's in the ballpark.