05 Trailblazer - how to tell if wheel bearings bad

[BoxMN]

So I think I might have a bad wheel bearing on passenger side of 05 Trailblazer, 4x4, about 170k miles. Just noticed on my drive back from up north the howling. Gets louder about 55 mph or faster.

We can't tell if from the front or rear. How can I inspect and tell which (if any) are bad? I believe jack it up and wiggle up/down and if there is play, that is it?.??.... Is that for the rear as well? I have put new fronts in k1500 before, but never done a rear bearing. How difficult is that?

Thanks for any advice.

Edited December 7, 2015 by BoxMN

[Macgyver55]

Trailblazer has a standard rear differential so it less likely to be a bad rear bearing  unless it has been run low on gear lube.   Front bearings are far more common to go bad on a Trailblazer  so I would recommend starting looking there first.  Jack up the front of the vehicle and check for any looseness in the bearings. If both feel tight try spinning them to see if there is any noise. I am more inclined  to believe you will find it to be a front hub assembly  that is bad  rather then a rear axle bearing.

[Jeremy airjer W]

Typically do not hear them that fast. I would check the tires for cupping first. Typically you will start to hear a bearing at about 30-40 miles an hour. You can then turn to the right or left and see if the noise gets worse or better. If you turn right and it gets worse its usually the left bearing as the weight of the vehicle puts more load on that bearing in the turn. The opposite for the right bearing.

A bearing can be loose and not make noise. There is an acceptable amount of play. If you grab the tire at 12 and 6 and push/pull you will be able to feel a sloppy bearing. If the bearing is really bad you should be able to spin the tire by hand while holding the upper control arm and feel and/or hear the bearing growling.

[BoxMN]

Thanks guys. Grabbing both fronts at 3 and 9 there is a little slop. But at 6 and 12 there is none. So that might mean I should plan tie rod ends maybe?....

But had my neighbor drive it, and no sounds this time, and nothing funky sounds wise or feeling wise while turning both ways. He said maybe it wasn't hot enough after just short drive. He told me to check rear gear lube which i will today. I will check front as well, but since I did the axle shaft seal it was full and I have seen no dripping since.

I will try the spinning the tire by hand and listen closely and feel for anything odd as well. Thanks much!!!

[bigpike]

I had an Envoy (GMC equivalent of Trailblazer) and the front hubs would groan at highway speeds when going around a curve.  Both went out over the time we owned it.  A growl on a curve to the right meant the driver side was bad, and vice versa.