Vibrations/Shaking on Hwy.

[sk8rdi16]

I have a pretty bad vibration/shaking at highway speeds. This really to me feels like unbalanced wheels. I just had 2 new michelin LTXs put on the front and ~2months ago 2 new ones on the back. The tires should be balanced! What else could it be? The vibrations continue when in neutral, so not trans related.
They sort of pulseate. It is not a constant vibration, and gets worse at higher speeds.

Thanks!

[bobt]

Could also be bad shocks on front.
Bob

[Hubert]

At 306,000 miles whew it could anything. U-joints, driveshaft etc output shaft. Been off road mud caked on anything? Look to see if maybe a wheel weight was lost or any tread imperfections etc Just had a friend who developed a bad little tire vibration and thread came apart before he could have a tire shop check it out. Front tires are usually felt in steering wheel back tires in seat of pants and back. Engine/tranny I feel through feet sometimes and feel it all over.

Does it vibrate sitting still revved to 1700-2000 rpm or what ever highway rpm is. Don't! romp on throttle but ease it up and around normal hwy rpms and search for any vibes could be dual mass flywheel going. Is it a auto or manual? shift ok etc?

[sk8rdi16]

It does have lots of miles! The engine only has ~160k, then tranny was recently rebuilt. It is auto. No mud caked up.
I do feel it in the steering wheel. The steering is also pretty loose. Maybe I could tighten the steering box? I also feel it in the seat of pants... The passenger seat back vibrates pretty bad, and also the spare tire in the back. Are the U-joints hard to change?

Thanks!!!

[slagona]

It could also be a broken belt in one of the tires. I had it happen to me once. It was like having a warped rotor sort of feeling - but only at certain speeds. I even went as far as replacing the rotors thinking they may have warped as I couldn't find anything else wrong.

I couldn't see anything wrong with the tires, but it did end up being a broken belt. Take it to a tire shop and have them checked.

[Hubert]

On second thought u joints usually clang or make a sound like "tingk" sometimes a "clunk" when you pull into gear reverse or forward when they are bad. Comes from the extra backlash / slop in the drivetrain. They will cause vibration when they get really loose or a cap tries to come out.

Inspect them feel for play in the driveshaft and grease em up if they have the fitting and see if it helps first.

No they are not real hard to change and a few tricks make it easier. I'll give you a few suggestions if you want to change them but with that many miles you could end up replacing a lot of stuff thats getting worn out but not causing the vibration. Not knowing everything and condition makes all this board advice a crap shoot. look at other stuff too.

The front end not sure? How old is it? idler arm tie rods and pitman arm? Ball joints etc. Are you getting any uneven tire wear? All play a part in steering feel but may not cause vibration you feel all over the truck. If you can see the back end vibrating it just sounds like the backend maybe tires even if they are realitively new.

I am saying it could be lots of stuff. Having a good shop help diagnose it might save you a lot of parts changing before its time. At 306,000 miles lots of things are getting tired besides the engine & tranny. It might pay to have an experienced tire man / front end shop look at it. Talk to 'em and some will help diagnose it and offer advice (for potential business)- you will need an alignment if replacing front end parts.

[Govt issue]

Ive been threw this on my truck. Take your truck to a shop that has a Hunter G Force Tire balancer/ Truer. I balanced my tires myself on my machine, They balanced out fine. But the vibration was still at 72 mph. It didn't start till after the new tires. I took it to A friends tire shop with his machine, It took out the vibration. Also if you have a slow steering wheel shake at low speeds 35 or so, just on certain roads, look for a bad tie rod.

[bigmikestud]

Go to: www.gsp9700.com (http://www.gsp9700.com) and you will find the nearest tire shop in your area with the Hunter "Road Force" balancing machine. Its even better if they have the 4-jaw chuck adapter........wheels as heavy as ours are difficult to get "centered" properly when balancing. My rig throws front inner wheel weights as fast as I install them. Try some gray permatex around your weights to keep them on, especially if you use tape on jobs. www.qsequipment.com (http://www.qsequipment.com) Mike Abernathey (816)726-6288 if you need balancing tips. :cool:

[TJ Moose]

Yeah - you can also pefectly balance a tire that isn't round due to a ply-separation (what I think one of the other responders called a broken belt in the tire) so it'll go around great on the balancer, and still drive you nuts where the rubber literally meets the road - because the tire is no longer round. And a ply-sep can start pretty quickly with no provocation, and can happen in the tread or the sidewall. Sometimes they're hard to spot unless you can eyeball it while rotating it (not recommended while you have you body duct taped to the bottom of your rig!) If your problem came up suddenly - I'd vote for a tire defect or a thrown weight. If its come on gradually - then probably front end wear, shock crap-out, or u-joint.

[sk8rdi16]

The Suburban has always had the shake. I bought the truck about 6 months ago. The trip home was MISERABLE! I soon after got the worst two tire replaced. That helped some, but not much. I thought once I got the other two replaced everything would be fine. It still shakes. I think tomorrow I will go to the nearest place with the road force in the am. Hopefully they can do it before I leave for my first real road trip to Austin at noon!
Could the problem be a messed up rim and the normal balanceing can't correct it? All of the tires have massive amounts of weights on them. It seems like all of the tire shops have a hard time balancing them. I took it to Wal-mart about 5 times and each time they said it wasn't previously balanced!

Oh yea, I will be towing a trailer full of my Veg Oil fuel!! and driving on it the entire way to TX (10 hours)!

Thanks all!!

[Hubert]

You bet a rim can cause problems. Probably why it requires so much wieght. Bent rims can cause problems too. Unevenly worn rotors/drums can cause problems etc. When tires are run with a lot of vibration over time they will wear into the vibration and must be trued or replaced to bring the tire/rim back to specs.

Walmart and high volume discount tire stores are a gamble sometimes. Lots of turn over and guys with jobs. They see mostly cars and sometimes only learn the common stuff and or are in it for the quick easy fix. They deal with volume to make money. You'll have to judge the technicians individually but try and find a good local shop with lots of experience that see the bigger tires, trucks, and/or SUV's.

[TJ Moose]

Amen to Hubert's comments. Bent rims can easily do the same - and I'd just never go to Wally's world for tires . To diagnose this - I'd be more willing to go to an honest to goodness "mostly all we do is tires" type shop. The closer to home the better, and even better than that, if they don't mind you walking back to wherever they're rotating the tire/wheel to look at it. (Insurance regulations be damned for just a few moments.)
Or - you can jack up one tire at a time in the driveway and just slowly rotate them next to a fixed object - lift the tire just off the driveway surface, stick your eyeball about on the ground, and see if it runs out or is egg shaped. Same with the rim - easy as setting a bucket with a stick on top of it right at rim height and turn the tire. If you see the rim edge wander out and back from the fixed stick - that's a pretty obvious place to start. Rims are easily bent, easy to check, and (if not custom rims) relatively cheap to replace. And it doesn't take much run out to cause a vibration problem.
You wouldn't think new Michelins would have a problem - but last set of 4 tires I got from a Les Schwab - Toyos - which are some of the roundest tires I've ever put on my wife's SAAB - must have been a bad batch - 3 of the 4 had a minimum 1/4 inch out of round using the "eyeball on the floor" garage test. When I went back to the dealer, they first started telling me my rims must be bent until they took a closer look at things. After they got their eyebrows back off the top of their forehead, they ran into stock and got me 3 new much rounder tires. But if your 'Burb has always shook, with everything else you've done, I'd look hard at the wheels. Even one bent one will ruin your whole trip....