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2006 chevy trailblazer_ls
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62 Posts
Discussion Starter · #1 · (Edited)
I have an 06 TB LS with 119,000 miles. When driving the drivetrain is fine for about the first 3 miles at about 45 mph. After that distance, I feel a distinct low vibration or hum coming from the front end. Here is a little service history of things I replaced:

1. At 79,000 miles replaced struts with Monroe quickstruts and front wheel bearings with Timken brand units.

2. At 100,000 I replaced the rear driveshaft bearings with regreasable Moog u-joints.

3. At 119,000 I just replaced a really bad driver side outer end with a Moog brand part. When driving it would wander side to side a lot.

To diagnose, I have several questions.

First, does the front driveshaft turn when driving in two wheel? If so, I am thinking here that the u-joints may be going bad.

Second, since the tie rod end was really bad, probably for the last 8~10 months, the hub bearing was exposed to a constant force pushing in a direction towards the wheel, since the tire was always turned a little to the outside. The center area of the tire does show more wear than either side of the center area. So here I am thinking front wheel bearing.

The front cv joints appear to be in good condition with no grease leakage or torn boots. The tires are BF Goodrich and have about 59,000 on them. They have good treadlife left and don't have any bubbles or humped belts.

Any help would be greatly appreciated.
 

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2003 gmc envoy_slt_xl
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116 Posts
Not going to be of much help however FWIW when my front hubs have gone bad, the hum shows up well before 45 MPH. Could be cupping or other tire wear causing the hum too. Good luck
 

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2006 chevy trailblazer_ls
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62 Posts
Discussion Starter · #4 ·
I wish I could remember how I determined what was the hum but I sold it 2 years ago. However, after I did the tie rod end replacement, I did a check on the lower ball joints and found each side to have excessive play. I replaced both lower ball joints and while there also replaced both upper ball joints and the tie rod end on the passenger side. Now that I think about it, that helped to make it go down the road quieter when I did a road test in neutral and let it coast. After that replacement work, I took it and had the front end aligned and that, combined with the parts replacement, really helped quiet the front.
 

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2006 Trailblazer LS 4.2L I6
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I wish I could remember how I determined what was the hum but I sold it 2 years ago. However, after I did the tie rod end replacement, I did a check on the lower ball joints and found each side to have excessive play. I replaced both lower ball joints and while there also replaced both upper ball joints and the tie rod end on the passenger side. Now that I think about it, that helped to make it go down the road quieter when I did a road test in neutral and let it coast. After that replacement work, I took it and had the front end aligned and that, combined with the parts replacement, really helped quiet the front.
(y) Thanks for letting me know and taking the time to share a bit of info.
 
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