2003 Excursion hum when accelerating slowly

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Jun 25, 2009 | 10:24 AM

PA Chuck

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2003 Excursion hum when accelerating slowly

After buying my 2003 Excursion I took a buddy for a ride, and he just happens to be a qualified service tech, and while accelerating slowing at around 35 mph he said "what's that sound?" I hadn't heard it before he mentioned it, but when accelerating slowly I hear this hum or vibration at 35 mph and it goes away around 40mph, and if I continue to accelerate slowly I hear it again at 50 mph and it goes away around 55. If I accelerate quickly from a stop I don't hear it at all. I've checked my front wheel hubs and there are in auto mode. This sounds like it is coming from the front of the vehicle.

Should I be concerned?

Jun 25, 2009 | 11:12 AM

DaveandJennyP

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From: Michigan

Mine has an exhaust heat shield that buzzes off an on. I have put a couple hose clamps on but haven't found the exact spot of the buzz yet. It's like you said only at certain times.

Jun 25, 2009 | 11:30 AM

PA Chuck

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Hadn't thought of that. I suppose that could be it. Much rather that than something in the drive train. Thanks!

Jun 26, 2009 | 12:05 AM

EXv10

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From: Mt. Shasta California

Probably something touching someting else just enough to produce a resonating effect at certain harmonic frequencies.

Jun 26, 2009 | 06:22 AM

myblkex

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From: Long Island - NY

Quote:

Originally Posted by PA Chuck

Mine does EXACTLY what you are describing. It only does it on light acceleration at around 35 and then again at 50-55. Feels like it's a droning/vibration down the front mid section of the truck.

I noticed that it is not speed relative though - but rather rpm. Take it out of OD and drive it the same manner and you'll see it no longer does that sound at those particular speeds - but instead at those exact rpms. It happens when you give it light throttle while cruising when the rpm's are at just about 1500-1600. It does not make the sound if you let off the gas during the drone or if you give it more gas and push through the rpm range...

I still have no idea what it is exactly though

Jun 26, 2009 | 06:29 AM

jdadamsjr

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Is it possible it is the radiator fan coming on due to heat ?

mine RARELY comes on and when it does, it could could a distant hum with the windows up and ac and radio blasting away....