front end noise above 40mph

[koenig65]

1998 Limited 5L AWD. noise is normal for AWD until 40mph and then it increases(humming) as speed increses. The front end was completely rebuilt 2 years ago. my wife drives the explorer and i drove it today and noticed the noise..she says it just started to get louder in the past few days. i will crawl under it and check it out and repost.....any help would be appreciated.

 

[Lizard]

I had a similar hum which turned out to be a right hub bearing. Jack it up and grab the tires at 6 and 12 O'clock positions and rock it. Any sign of play probably means bad bearing. Another test is to drive at the speed where you hear the noise then change lanes quickly. If you turn left and the noise gets worse then it's the right bearing, and vice versa.

 

[koenig65]

absolutelly no play at all when i try to move the wheels with hands at 6 and 12.