Offroad Trailblazers and Envoys

Looking for some advice

Trailblazer and Envoy related, but not off-road related...

by Shdwdrgn » Fri Dec 08, 2017 8:00 pm

A couple years ago I got hit on the front end by a kid. Basically I was coming down an open left-turn lane, and she decided to pull into that lane right beside me. Both front wheels collided, mine breaking out a piece and her steel rim collapsing. Since then I have...
- Checked the frame (no damage found)
- replaced the lower passenger control arm and ball joint (bent)
- replaced the steering rack (gearing was damaged)
- had many (MANY) realignments done

The bulk of the labor has been done by Big-O who I actually trust more than any other mechanic I've tried in the area. After the obvious damage was repaired I told them it was still pulling to the left (remember I was hit on the right). They can compensate the alignment but that doesn't really fix the problem... Since buying this truck it has tracked extremely well down the road, and cross-winds had almost no effect on it. Now it is fairly sensitive to wind and any roll in the road. I know something is still out of whack but nobody can seem to pinpoint what exactly, so in the meantime I've just been waiting to see if something wore out. The most noticeable issue is when turning on the road, which I noticed immediately after the accident. Imagine you are driving down the inside of a tube. If you drift to one side, the curve of the tube would tend to push you back towards the center again. When I'm driving now it feels like I'm always against the right side, being pushed to the left. If I try to turn left, it goes immediately. If I try to turn right, there is a pressure and I have to turn the wheel harder.

After a long trip last weekend, it finally happened. Over the Summer I've developed a noise which the mechanics thought was just tire noise, except it only came from the front. This week that noise has suddenly gotten much louder and now has a definite pulsing in tune with the axle rotating, even at low city speeds. It's definitely a friction sound, but placing the location of it has been impossible. It sounds like it is coming from near the center, just in front of me, but possibly a bit to the left of center? Yeah I dunno exactly.

What I do know is this... It makes no difference if I'm in 4WD. There is no change when I hit the brakes, although it does sound a little louder when turning right, and quieter when turning left (I mean at highway speeds, going around curves, there is no difference when simply making a turn at an intersection). I checked the front differential fluid last month, it is full to the plug and has no unusual smell. The front tires are also wearing heavily in the inside corners (more so on the driver's side tire). Note the last two sets of tires before the accident wore perfectly even.

So with the obvious friction sound becoming worrisome, I took off work today. Since I got hit on the right, it seemed more likely any damage would be on that side, plus it allowed me to also check the half-shaft through the oil pan. Unfortunately, I found nothing at all. The bearings in the wheel spin fine without any drag. I can't feel anything wrong with the axle or the joints at either end (although the boots are still pretty stiff so it's difficult to say for sure). I popped open the unit that engages 4WD, but there's no wear and the bearings all roll smoothly. I *thought* I saw some wear on the end of the half shaft, but once I pulled it out and wiped it down I could see all the appropriate surfaces still have the expected polish and nothing shows any sign of wear. I even rolled it across the garage floor, but it appears nicely straight. With the despair of defeat, I put everything back together again and plan on giving the same treatment to the driver's side on Sunday...

With all that said, one thing I haven't looked at is the front driveshaft. It is certainly possible that the wear I am hearing is unrelated to the accident, but I don't know what to look for. I *have* made a couple inspections with the light, looking at the seals across the path of the front axle for any signs of oil leakage, but so far have not found anything. I can only hope I find something on the driver's side.

That's pretty much what I know at this point. Hopefully there are some ideas for what else to check in to, both for the friction noise and for the alignment issue. This is probably going to be the last burst of warm weather I see before Winter really sets in around here, so I'm doing what I can with the time.
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Shdwdrgn
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by NC_IslandRunner » Fri Dec 08, 2017 8:43 pm

Wait your front driveshaft is 2yrs old? mine never last that long.Lol

For real, you may never find it, could have tweaked something a little and you never find it, but spend the bank trying. It could have messed up the frame slightly and it is just not visible, or it could have tweaked a dozen thing a millimeter each, either way you may be chasing a ghost.

See if there is any play where the driveshaft enters the front diff on the drivers side, push up and down, shouldn't move. Mine made a little noise when it went bad, and I rode it until it have waaaaaaay too much play.
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by Shdwdrgn » Fri Dec 08, 2017 8:59 pm

My driveshaft is OEM, never been replaced. The truck has about 143K miles on it. I'll check for play on Sunday when I have it jacked up again. I would never have thought a driveshaft would be something that would wear out!

The frame was checked by a local frame shop. There is a 4mm drop in the front end which they said may mean the previous owner got the truck airborne. There is zero sideways play in the frame, nor any twist. One possibility based on my own measurements is that the top A-frame on the passenger side seems to be about 1/4" further forward than the driver's side. Of course this is based on a tape measure against other reference points on the frame and measuring from the real wheels, but nobody seems to have the equipment to make a proper measurement, nor was anyone able to tell me how to straighten the mounts for the A-frame if they were bent. And it's not something I think I should try adjusting myself for fear of weakening the mounting points.
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by NC_IslandRunner » Sat Dec 09, 2017 12:51 am

The fronts are CV driveshafts, anyone who has wheel a trailblazer has replaced them. I've done each 2-3 times so far, I'm only at 177K miles.
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by Anthony Hernandez » Sat Dec 09, 2017 8:55 am

could it be that your upper or lower control arms got tweaked? possibly the tie rods bent?
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by Shdwdrgn » Sat Dec 09, 2017 11:12 am

Anthony - yes the lower control arm definitely. I had actually just replaced both sides a few months before so I could see that the one on the side I got hit didn't look right. After replacing that things improved considerably. As for the upper... it certainly seems possible and like I said the brackets where the upper mounts to the frame also appeared to measure wrong, so something in that region seems a likely culprit. Replacing the upper (I called it the upper A-frame above) would be easy enough, but what can be done if the mounting points were twisted?
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by Trail X » Sun Dec 10, 2017 4:59 pm

Shdwdrgn wrote:After a long trip last weekend, it finally happened. Over the Summer I've developed a noise which the mechanics thought was just tire noise, except it only came from the front. This week that noise has suddenly gotten much louder and now has a definite pulsing in tune with the axle rotating, even at low city speeds. It's definitely a friction sound, but placing the location of it has been impossible. It sounds like it is coming from near the center, just in front of me, but possibly a bit to the left of center? Yeah I dunno exactly.

What I do know is this... It makes no difference if I'm in 4WD. There is no change when I hit the brakes, although it does sound a little louder when turning right, and quieter when turning left (I mean at highway speeds, going around curves, there is no difference when simply making a turn at an intersection). I checked the front differential fluid last month, it is full to the plug and has no unusual smell.


^ That description sounds exactly like a wheel bearing to me. The difficulty is in determining which side of the front end the bad bearing is located. In the past, when it wasn't obvious, I jack the truck up, and spin each wheel individually by hand. Once the bearing gets bad enough, you'll be able to hear a little bit more grinding on one side. The only other possibility is one of your front brakes dragging slightly, maybe on some rust. Normally brakes dragging are a higher pitch, and bearings are lower.

Shdwdrgn wrote:The front tires are also wearing heavily in the inside corners (more so on the driver's side tire). Note the last two sets of tires before the accident wore perfectly even.


The only explanation there is bad camber or toe. Have you ever attempted to measure your toe or camber yourself?
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by Shdwdrgn » Sun Dec 10, 2017 7:42 pm

Trail X wrote:^ That description sounds exactly like a wheel bearing to me.


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So per the previous discussion, I checked prices this morning and was surprised to find new CV axles were only $70 for new ones with full lifetime warranties. I went ahead and asked them to get me two (which they were able to have at the store by 1pm) and then proceeded to pull apart both sides. As expected, I didn't find any issues on the driver's side. So them I pulled the passenger side apart again, and damnit, I completely missed this on Friday but the wheel bearing was most certainly shot to hell. Spinning it with the tire off there was no question that not only was it dragging, but I could also feel metal-on-metal contact. Called the parts store back, and yes they had a replacement wheel hub, plus the new axles had arrived. Drove the wife's car to pick up parts, grabbed some lunch, and then got to work.

So when this noise first started earlier this year, Big-O suggested that it could be a wheel bearing, but we all thought it sounded like it was on the driver's side. So I had them replace the bearings on that side... at a cost of $300. Ouch. And of course it didn't fix the problem. The combined total of all the parts today (including a new low-beam bulb) came in at less than $300. I wish I'd known it was so easy to replace the hub, but I was impatient at the time.

The new axles came with 36mm nuts. My stock axles had 35mm nuts, and I already have the socket. Not gonna deal with that, so luckily they were the same thread, and my OEM nuts also have a monster washer attached. Just seemed like the better solution. Greased up the new splines and slid everything back together with no problems. Got the new hub installed and routed the sensor wire (yay no more zip ties!). Altogether including trips for parts and time for lunch I only spent 5 hours completely rebuilding both sides, which is similar to the time it took me on Friday just to do the one side. Amazing how much faster it goes once you know to just pop the top and bottom ball joints and not mess with the shock tower or anything else. And I even remembered to replace the oil that had drained from the front differential while the axle was out (gotta remember to get a new bottle, I have only a drip left in the old one).

Test drive was amazing. It really felt like it was back to original condition again and the steering no longer feels like I'm being pushed to the left. In fact the alignment seems to be drifting to the right now because they had compensated to get it to drive straight. I'll try to get that fixed this week as I need to take it back to Big-O anyway... the new steering rack they dropped in a couple months ago feels like it's stuck when trying to turn the wheels while standing still. I checked the fluid level and tried to work out any air by turning it fully from one side to the other, but it's just not feeling right. If they have to replace it again, this will be the third one they've installed in less than 2 years, and I'll be asking them to switch to a different brand before the warranty runs out and I have to replace one on my dime instead of their's. Whatever they do with that, I'll ask them to also do a new alignment without any compensation and see if the truck tracks straight again.

The one thing that annoys me... I can't understand if the right wheel bearing was bad, then why was the truck pulling to the left? I would expect the drag to pull back the wheel on the bad side and make the steering also pull to that same side.
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by Trail X » Mon Dec 11, 2017 12:02 am

Not sure about that one. My only thought is that the added play in the bearings was throwing off their alignment attempts. A tilted tire does want to turn towards the way it's tilting.
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by Shdwdrgn » Mon Dec 11, 2017 12:19 am

My suspicion is that the wheel hub was damaged and probably bent from the force of the impact, however I thought alignments were performed with a tool attached directly to the wheel? Seems like that should ensure the alignment was square to the tire no matter how the pieces behind it may be bent, but I dunno, alignments are black-magic to me. I will certainly be interested to see what happens after the next alignment though...
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