I have a ' 97 Geo Tracker 2 door convertible 4x4 with 5 speed tranny.When I have the manual lock-outs engaged, whether in or out of 4 wheel drive, I sometimes get a noise like "wa-wa-wa-wa. If I hit a small bump in the road it stops. Next time I hit a bump it might start up again.My question is: if this is a bad wheel bearing, wouldn't it make that noise with the lock-outs disengaged also, since the bearing is still carrying the weight of the vehicle? I'm just trying to pinpoint the problem. Any thoughts on this? P.S. The noise speeds up and slows down according to vehicle speed.