Picked up my 97 at the end of 2009. It has always had a bad shake when driving.......

I just replace the control arm bushings with poly bushings. No change in the shake. Tires are balanced. I just put in new axle u joints on both sides. I have 3 gen track bar. New drag link. And all other front end components see to be in good shape. U joints seem to be fine as well.

I am leaning towards shocks, un balanced drive shaft. Or drive shaft u joints are bad enough to cause the shake......

When on the freeway I can put the clutch in and it still shakes. Put it in neutral and it still shakes..... Shakes from 30 mph and up.

And when I hit bumps in the road it still seems like I have a bad track bar....

I just did the poly control arm bushings on Monday. I did not have it realigned yet. But I don't feel it's alignment caused. My truck does not pull down left or right down the road at all......

I love my truck. But the shaking is killing my 12 valve spirit....... ha ha

 

Does it shack going straight, turning, all the time? Is one situation worse than the other?

My wife had a bad shake in her Bravada a couple years ago. It turned out to be a broken belt in one tire. Since we knew we were going to be replacing the tires in a couple months, we balanced the tire and put it on the rear to get us by. It still did it, just not as bad, but caused a shake non the less. I'm wondering if what your experiencing is a broken belt.

Also, even though you said you suspect the u-joints are good, they may not be. I just finished replacing all the u-joints on my truck. I had several that showed no movement when checking them, but, were sticking when I got the shafts off the truck and tried to move them. I had an axle u-joint do that once that caused a heck of bump through the steering wheel when turning. It's not hard for me to imagine a sticking driveshaft u-joint causing a shake. I'd look at the double cardan cv joint on the front driveshaft too.

As for an out of balance drive shaft, I'm not so sure. Look for dents and missing wieghts. If there's no sign of any of that, then the shaft is probably still balanced. The only out of balance shaft I ever experienced made the vehicle undriveable...it caused that bad of a vibration. I am curious if you've ever had the driveshaft off the truck? If you didn't install it in exactly the same orientation as it came off by marking the yoke and shaft ends to insure proper orientation, that could be a posible cause of your shake.

Good luck!

 

How are those ball joints?

 

Thanks for the reply guys. Everything under the front end seems good. I have checked everything several time as well as my local tire shop. Obviously it's something I am over looking......

 

Just for kicks, does your truck have a 2-piece driveshaft? If so, check the center support bearing. There should be some movement allowed, only in the rubber isolator, if you hear/feel a little click/clunk when you move it, that caused some vibrating problems in my truck, with a balanced driveshaft assembly.

PS caster alignment is done through the off-center bushings in the control arm. Too shallow of an angle can lead to vibration, as the tires won't "follow" like they should, and will fight any difference in traction.

 

gorms thanks for the info. I will check that tomorrow.....

Here is a an update on my shaking......

Installed poly urethane control arm bushings..... Still shakes.

I have had the front end off the ground and have checked every ball joint several times AGAIN.....

Only one ball joint is some what loose and that is the tire rod end on the passenger side....

Truck shakes at all speeds above 35. If I accelerate the shaking will go away for a few second but come right back when I am at a steady speed again....

As Hercules mentioned. I am starting to think it's bad tires. I am going to put my snow tires on and see if it still shakes...... I purchased a set of Pro Comp Extreme AT's that where used with 60% tread. Tires where worn evenly and no visual issues. And they balance out fine......

 

maybe its a bent rim, could even be on the rear, something else to check.

any chance you can hang out the window at the same time you feel the shake, and actually watch the front wheel?
I had what I was certain was NOT death wobble, as it felt like an up/down movement, when I managed to get my head out the window and look it actually was a side to side or death wobble

 

Nick I was actually thinking about mounting my helmet cam under my truck to see what is going on.........

I have the 3rd generation track bar. But the shake does feel like a bad track bar..... When I hit certain holes/bumps on the highway the front end seems to shift.

Let me ask this..... After I installed my new control arm bushings I had my nephew start the truck up and pull forwards and then stop. The axle seem to roll a lot on my truck. I would have thought the axle would stay pretty much in the same spot with upper and lower control arms. Is it normal for the axle to roll when stopping? And if this is not normal what would allow my axle to rotate when I hit the brakes?

 

Another thing to check I guess will be the shocks...... Anyone had bad shocks that would allow the truck to shake badly?

 

if it looks like the axel/wheel is moving back and forth in the wheel well, then there would be an issue with your control arms, I have seen the bushings "pop" out of the control arms after being installed, mine had to be tack welded in place,

when braking the wheel must stay centered in the wheel well

 

Change to the HD steering set up the tri y sucks. What lift do you have if any as one size listed is 32" and the other is 35". Is it vibration or shake of the steering wheel. If it is a shake you can rule out drive shaft and front u-bolts. It does sound like a trac bar does it get worse when you hit a bump? This is when the steering would get real bad. Take some pics of your front end underneath and post them.

 

Nick thanks for the info...... The wheel does stay centered. I just was surprised on how much the axle would roll when I hit the brakes.....

BigGreen my tires are 305 Pro Comps. They measure 31.5" tall....

I don't get any shake in the steering wheel. It's a shake that shakes the entire truck... When I hit bumps the truck seems to shake side to side just like a death wobble. But when I get under the truck and have someone turn the wheel the track bar is nice and tight.....

I purchased the 3 gen track bar from a guy with a 2003 that had 65,000 miles. The bushings in the track seemed good. How many miles do the 3rd gen tracks bar bushings usually last?

 

Well the ball joints are hard to check sometimes. Do you have experience with them not trying to insult your intelligence but don't know you. These ball joints suck and it does not take very much play to screw things up.

 

No offense taken BigGreen.... I have had two shops including my self check the front end. I am going to give it one more good look this weekend.....

 

Here's a long shot. check the slip joint in the driveline.

I have been having a shake in the truck for quite a while, and no luck finding it, so to heck with it. the other day, I was doing a service, and decided to really gorilla grip the two halves of the driveshaft, and give it a twist. Sure enough, there is some serious slop in the slip joint splines. Enough that you can feel it clunk when you are on and off the throttle quickly. I thought it could be tranny, t-case, or rear diff, but they all check out perfectly fine.

Goes to show that there are strange things done in the midnight sun...