1998 Jeep Grand Cherokee

Noises problem
1998 Jeep Grand Cherokee 6 cyl Four Wheel Drive Automatic 170000 miles

I have replaced Pads, rotors, and wheel bearings myself. The sound is a full time sound that increases pitch with speed. The sound only goes away while making a 90 degree turn left or right. The rotor splash gaurd is not rubbing. I think the only possible culprit remaining is the half axle. It has a boot on it. Is there a test/something I could do myself to confirm it's the axle? I dont have a problem with taking the Wheel bearing off again if I have to.
October 28, 2010.

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