Trailblazer LS 2wd. When driving straight, the truck sometimes feels a little unstable-reminds of driving a moving truck when empty,how its a little shaky unless it's loaded,if that makes sense. I can't see anything visibly wrong. Corners fine,just feels weird on the straightaway. Dont know if it's related,but about a month ago, the Stabilitrak light came on for 2 days, then went off and has stayed off since.
Stability weirdness
- Thread starter sunliner
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Chickenhawk
Member
- Dec 6, 2011
- 781
Any groaning noises that seem to go away when turning in one direction? It will start off as a faint groan; almost imperceptible. More of a feeling. It will steadily get worse. That's a wheel hub going, and can also cause the Stabiltrak light to come on when you lose the speed sensor readout at the ABS in the hub.
The other one that is equally likely is wear in the outer tie rod ends. Reach underneath with the truck off and grip the outer tie rod end with your hand, right at the outer end at the ball joint. Get someone to turn the steering wheel slightly in both directions. (Engine off.) If the tie rod end is worn, you will instantly feel the play in the tie rod end when it starts to move with the wheel turning slightly but the ball joint end does not yet move. Subtle, but if you try it, you will feel exactly what I mean. ANY play means they need replacing. This is one of the biggest causes of a "feeling" of wandering on the highway without it actually wandering.
Let us know.
The other one that is equally likely is wear in the outer tie rod ends. Reach underneath with the truck off and grip the outer tie rod end with your hand, right at the outer end at the ball joint. Get someone to turn the steering wheel slightly in both directions. (Engine off.) If the tie rod end is worn, you will instantly feel the play in the tie rod end when it starts to move with the wheel turning slightly but the ball joint end does not yet move. Subtle, but if you try it, you will feel exactly what I mean. ANY play means they need replacing. This is one of the biggest causes of a "feeling" of wandering on the highway without it actually wandering.
Let us know.
I don't note any groaning sounds, but to be fair, my hearing sucks. I got under the truck and let my son turn the wheel. I don't notice any lateral play in either rod, however I can rotate the passenger side tie rod slightly with a moderate amount of grip. Thanks for the hint
It is VERY Difficult to determine the condition of the Front Suspension of a Mid Sized Truck or SUV by simply trying to move things around by hand. What you are describing is symptomatically similar to having a "Driving on the Top of an Egg" sensation... and is technically called: TOE.. More specifically in your situation TOE OUT. @Chickenhawk has nailed it with the need for New Ball Joints and Tie Rod Ends that will also require a proper subsequent Front End Alignment. Don't wasts the time and money trying to have the truck aligned B4 this repair is performed thinking that by re-adjusting things it will take care of the matter. It will not.
Chickenhawk
Member
- Dec 6, 2011
- 781
MRRSM has a very good point. Toe alignment is actually critical to the feel, and I like his description of "driving on top of an egg."
I think we would both suggest a wheel alignment from a GOOD garage, not some chain that tries to up sell you on unnecessary parts. They will be in a better position to check ball joints for wear, and if they tell you the tie rod ends need replacing (which is quite common after 120K miles or so) you can try the trick I told you about above to feel for yourself if they are scamming you or they legitimately need replacing. Once it is up on a rack, you can actually see the play in the outer tie rod ends if you look real closely. Tie rod ends should normally be able to rotate slightly because that is what they are designed to do. If they seem to rotate too easily but the outer end is tight, it may be a sign that the inner tie rod ends are worn. (Much less common but possible.)
If you know your way around suspension parts and know everything is tight but suspect the toe setting just may be out (or have replaced the outer tie rod ends yourself and need to bring toe back into alignment) there are ways to adjust toe yourself in your driveway. It requires jacking up the whole front end, placing it on jackstands and adjusting tie rod ends an 1/8 of a turn at a time. It also requires a LOT of patience. But if you do it right and are VERY precise, you can actually get toe settings as close as a modern computer alignment machine. But this only applies to toe settings. (The Trailblazer platform likes a very slight amount of toe-in at the front.)
If you suspect the toe settings may be out, you can also use this method as a rough check to see of toe is really the problem. As MRRSM suggests, too much toe-out will really exacerbate the "driving on top of an egg" feeling.
I think we would both suggest a wheel alignment from a GOOD garage, not some chain that tries to up sell you on unnecessary parts. They will be in a better position to check ball joints for wear, and if they tell you the tie rod ends need replacing (which is quite common after 120K miles or so) you can try the trick I told you about above to feel for yourself if they are scamming you or they legitimately need replacing. Once it is up on a rack, you can actually see the play in the outer tie rod ends if you look real closely. Tie rod ends should normally be able to rotate slightly because that is what they are designed to do. If they seem to rotate too easily but the outer end is tight, it may be a sign that the inner tie rod ends are worn. (Much less common but possible.)
If you know your way around suspension parts and know everything is tight but suspect the toe setting just may be out (or have replaced the outer tie rod ends yourself and need to bring toe back into alignment) there are ways to adjust toe yourself in your driveway. It requires jacking up the whole front end, placing it on jackstands and adjusting tie rod ends an 1/8 of a turn at a time. It also requires a LOT of patience. But if you do it right and are VERY precise, you can actually get toe settings as close as a modern computer alignment machine. But this only applies to toe settings. (The Trailblazer platform likes a very slight amount of toe-in at the front.)
If you suspect the toe settings may be out, you can also use this method as a rough check to see of toe is really the problem. As MRRSM suggests, too much toe-out will really exacerbate the "driving on top of an egg" feeling.
We have a shop in town that Ive been going to for almost 18 years. Great guys,and it's been a while since I've given them a few C notes. Maybe it's time, Lol! Just eyeballing it from the front, I would swear that the drivers front wheel is straight & the pass side wheel is toed out a few degrees. I could replace the rod and ball joint if I had the time but i don't, plus I don't wanna throw parts at it without knowing for sure. I'll get the alignment checked at the shop and see what's up. I appreciate you guys!
Chickenhawk
Member
- Dec 6, 2011
- 781
Sounds like you have a good shop. They will tell you what needs replacing first because if they know what they are doing, they can't even align it properly with worn parts.
As for eyeballing the toe, the human eyeball is actually pretty precise. Here is an interesting bit of trivia about the Trailblazer. The front fender lip just above the tire is almost exactly parallel to the tire line, and you can use it to compare side to side. Next time you park it, park it with the wheel dead straight then eyeball the line of the wheel in comparison to the line of the fender lip when viewed from directly above. Actually, the fender line is very slightly narrower at the front than the back, but the front tires should have a bit (about 1/2" to 3/4") of toe in anyway. If you get really ambitious, lay or bungee a straight piece of wood across the wheel and tire, parallel to the ground as close to the center as possible. Then eyeball that stick from above. If there is a difference side by side, you have found your problem.
Just for fun and future info for others reading this thread, this is actually the way I get my toe roughly adjusted in my driveway when I replace outer tie rod ends. I use L-shaped or U-shaped aluminum channel, about 3 feet long, bungeed to my wheel. Once I get both tires exactly the same and both absolutely dead straight in comparison to the line of the fender lip, I use two tape measures stretched across from tire to tire, one on front and one behind. (This is the part that takes the time to be precise, and one will dive underneath the truck about 40 to 50 times before it is perfect.) If you work carefully, you can get the toe as precise as any computer alignment machine. Assuming the fender line is straight, with no damage, I get both sides exactly the same and exactly parallel to the fender line, then start adjusting toe in so the back measurement is 3/4" greater. The slow part is that every adjustment has to be halved from side to side to keep the wheels exactly the same and exactly dead straight. (Be sure the steering wheel does not move from dead straight.)
Another interesting bit of trivia. This method of eyeballing the toe and then measuring with two tape measures is what we used to do in the 1980s when we adjusted the toe on our endurance road race car. We used a bit of toe in for long tracks where we needed stability on a straight line, and a bit of toe out for short tracks to help it nip into a corner quicker. (Toe out makes it more challenging to drive in a straight line though.)
So, just for fun, go eyeball your wheel line in comparison to the fender lip when viewed from above, and you will see what I mean. If the wheels seem to be pointed outward slightly, even by a little bit, your toe is out. If one is pointed dead straight and the other is pointed outward slightly - which is what I suspect - then you have found your problem.
As for eyeballing the toe, the human eyeball is actually pretty precise. Here is an interesting bit of trivia about the Trailblazer. The front fender lip just above the tire is almost exactly parallel to the tire line, and you can use it to compare side to side. Next time you park it, park it with the wheel dead straight then eyeball the line of the wheel in comparison to the line of the fender lip when viewed from directly above. Actually, the fender line is very slightly narrower at the front than the back, but the front tires should have a bit (about 1/2" to 3/4") of toe in anyway. If you get really ambitious, lay or bungee a straight piece of wood across the wheel and tire, parallel to the ground as close to the center as possible. Then eyeball that stick from above. If there is a difference side by side, you have found your problem.
Just for fun and future info for others reading this thread, this is actually the way I get my toe roughly adjusted in my driveway when I replace outer tie rod ends. I use L-shaped or U-shaped aluminum channel, about 3 feet long, bungeed to my wheel. Once I get both tires exactly the same and both absolutely dead straight in comparison to the line of the fender lip, I use two tape measures stretched across from tire to tire, one on front and one behind. (This is the part that takes the time to be precise, and one will dive underneath the truck about 40 to 50 times before it is perfect.) If you work carefully, you can get the toe as precise as any computer alignment machine. Assuming the fender line is straight, with no damage, I get both sides exactly the same and exactly parallel to the fender line, then start adjusting toe in so the back measurement is 3/4" greater. The slow part is that every adjustment has to be halved from side to side to keep the wheels exactly the same and exactly dead straight. (Be sure the steering wheel does not move from dead straight.)
Another interesting bit of trivia. This method of eyeballing the toe and then measuring with two tape measures is what we used to do in the 1980s when we adjusted the toe on our endurance road race car. We used a bit of toe in for long tracks where we needed stability on a straight line, and a bit of toe out for short tracks to help it nip into a corner quicker. (Toe out makes it more challenging to drive in a straight line though.)
So, just for fun, go eyeball your wheel line in comparison to the fender lip when viewed from above, and you will see what I mean. If the wheels seem to be pointed outward slightly, even by a little bit, your toe is out. If one is pointed dead straight and the other is pointed outward slightly - which is what I suspect - then you have found your problem.
Well, I found a clue....I got under the beast tonight to get a better look at the tie rods and ball joints. first thing I noticed is that both front tires are slick as hell-wires partially showing-on the inside perimeter. I last rotated the tires just over 6400 miles ago, and they looked good. Total of 44,743 miles on them. This is embarrassing as hell...I usually keep an eye on these kinds of things. I just checked tire pressures last weekend but never thought to inspect the entire surface. So, I'm gonna get my favorite shop to write me for tires and a front end check...
well for those still following the saga...shop -Jim's Auto Service in Lake City, FL- checked the beast over and found it just needs an alignment after all. And of course, new tires. That's why I'm loyal to this shop....this is the latest of several times that they could have sold me a bunch of stuff I didn't need and I wouldn't have known the difference. They're not always cheap, but they're honest and 99% of the time they fix the problem on the first pass.
Chickenhawk
Member
- Dec 6, 2011
- 781
Good to hear. What was the final report on the specs? Did they give you the readouts? I bet camber was way off, and possibly toe as well.
they had to order the tires, so the work won't get done until tomorrow (thursday). I'll try to get the readout. Something must have gone to hell quickly though.Tires looked good when I rotated them last, but what I saw last night scared the hell out of me...usually just an around-town driver but just two weeks ago we took it down the interstate about 120 miles. It's a wonder the things didn't delaminate on me then. Didn't even notice any ride issues until last week.