04 Explorer, recently serviced, loud hum..transmission? | Ford Explorer Forums - Serious Explorations

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04 Explorer, recently serviced, loud hum..transmission?


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February 26, 2009
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I'm at 89,000 miles on my 04 Explorer 4.0 and lately it has an odd hum/while at speed. Took it in for preventative stuff, coolant flush, new plugs, and they replaced right front wheel bearing. It felt a bit smoother but the hum/while noise keeps getting louder. It shifts smoothly, no slipping, no clunking, but this whine/hum has me worried.

Any guesses? Transmission, etc? I am expecting the worst as this noise is only getting louder over the past few weeks. To me, it sounds like it is coming from the front of the vehicle and I can ever so slightly feel it in the floor and gas pedal. Even the transmission flush did not fix the issue.


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My guess (just from experience) would be the other front bearing.
That is how mine started, then I could feel it through the floor, the pedals, then eventually the steering wheel.
At speed rock the car side to side (sort of like nascar does on pace laps) does it briefly go away during the rocking?
If so check the other bearing.

Do all of your tires match and have even tread wear?

I know my rear end whines like a ***** and it's been replaced 3 times.

Brand new tires about 5000 miles ago all around. Hopefully it is a wheel bearing rather than transmission issue. I do notice that at 65-70mph I have to raise the stereo to drown out the whine.

......rather than transmission issue. I do notice that at 65-70mph I have to raise the stereo to drown out the whine.

In my experience, whine or hum is rather unusual from an automatic transmission, unless it occurs only in a range where gears are working under load and are damaged. Very loud growling noise has been heard due to torque converter damage, however.

Since the front differential gearing turns all the time it would also be suspect, in my view. imp

I say rear bearing.

Happened to me, I replaced the front left and in the end I took it in to ford to have them do the left rear( i didnt want to mess with it) . All quiet now.