Started humming and vibrationg

2002 JEEP GRAND CHEROKEE
215,000 MILES • V6 • 2WD • AUTOMATIC
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PRINCESS77ASH
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Took drive last night. Speed limit went from thirty five to fifty five. Road was windy and hilly. Got to fifty mph and vehicle started making humming noise and vibrating. When slow speed it stopped. driving in it now on straight road speed limit fifty five and still doing it. Come to a town speed changes to thirty five mph and now its doing it at slow speeds too. What are possibilities of what all could be wrong?
Mar 10, 2017 at 5:49 PM
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CARADIODOC
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ninety nine percent chance it is a noisy front wheel bearing. Best way to verify that is to run it in gear, on a hoist, and listen next to each bearing with a stethoscope. Sometimes you can also spin the wheel by hand, and feel the vibrations in the coil spring. That is the only option with rear-wheel-drive.

You can also use a "Chassis Ear" if you can find one at an auto parts store that rents or borrows tools. You clip microphones to suspect areas, then listen through head phones or a speaker while on a test-drive.
Mar 10, 2017 at 6:37 PM
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PRINCESS77ASH
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No it is not that. We have bad wheel bearing at the moment. When this noise is happening, you can still hear the wheel bearing also. Wondering if maybe transmission or engine is going bad? Does have 215,000 miles but has always been taken care of oil changed on time and all the other things. But has no other symptoms of transmission or engine going bad. No slippage no leak. Someone also said maybe torque converter?
Mar 10, 2017 at 6:55 PM
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CARADIODOC
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Tie up the radiator fan so it cannot free-wheel in the wind. If the noise is gone, replace the fan motor. The clues are the speeds you listed at which this occurs, and it is less likely to occur in warmer weather or after the vehicle has been in a warm shop or garage for a while.
Mar 10, 2017 at 7:10 PM
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PRINCESS77ASH
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Well see they had recall on the fan motor. We just had it replaced. Also, yesterday when it first happened it was pretty warm out. Upper sixties. Another thing, yesterday it only did it at higher speed of fifty and up. Today when we were driving it started doing it as we were going slow also. twenty to twenty five mph and it started. It has us stumped and honestly kind of scared to drive it in case we get stranded somewhere with two kids. Husband works long hours so by time he gets home it is too dark to crawl under. Finally gets day off tomorrow so going to try to take to friends garage to crawl under and check stuff out and have warm place to just check everything out. Trying to get some ideas of where to start looking for problems. Like I said its not the wheel bearing because we know it is bad and you can hear it is a totally different noise from that as we can still hear the bearing and the new noise. Not thinking fan because it was just replaced and it is now happening at different speeds. Slow and fast. Warm and cold weather. Totally stumped. Praying something cheap and easy. Praying not engine or transmission even though the miles are pretty high. But when I look at problems of engines and transmissions going bad, does not have a lot of same signs. Engine light does not come on, no leaks , no slippage.. No clue. ha ha!
Mar 10, 2017 at 7:58 PM
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CJ MEDEVAC
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Different and better looking person.

While you are under there,

Might check them Universal Joints too!

Level ground/ chock the wheels/ out of gear.

The Medic
Mar 11, 2017 at 5:34 PM
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PRINCESS77ASH
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Did not get to make it to the garage today, but he is taking it down tomorrow for sure. And thanks i will definitely tell him to check on that. Hopefully its something simple.
Mar 11, 2017 at 6:04 PM
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CARADIODOC
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There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.
Mar 12, 2017 at 2:13 PM
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PRINCESS77ASH
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Thanks! He is outside checking things out right now so hopefully we can find an answer today and hopefully it is decently good news!
Mar 12, 2017 at 2:54 PM