1997 Mitsubishi Montero

Shakes or Wobbles problem
1997 Mitsubishi Montero 6 cyl Four Wheel Drive Automatic 167, 00 miles

A few days ago, I noticed a slight vibration and associated noise:

The vibration is felt all-over---steering wheel, seat, it even makes my side mirrors vibrate. The associated noise sounds like a helicopter or train---not an abnormal sound, more like a big amplification of a normal noise, and very rhythmic.

Truck starts normally. I first notice the noise/vibration once I get up to ~40 mph. The noise/vibration will increase in intensity to a moderate level. It is only present when driving over 40 mph, and only lasts ~4 minutes after it starts. After 4 minutes, it will quiet and then completely resolve, and will not recur no matter how long or what type of roads I'm driving on.

It doesn't matter how warm the truck is----I drove it to class and the above-described occured. Stopped home for ~10 minutes and then left again, and it happened again just as above.

No change in how it shifts or runs overall.

Hx of recent brake caliper/rotor/pad change on the R rear, lower ball joint replacement L front ~4 months ago. Transmission replaced ~8 months ago, though alternater turned out to be the problem, and that was replaced as well.
May 5, 2010.

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