Help! Bad Vibrations/shaking

[CoMarc]

Here's the story:
So I put in the front diff drop bracket (had a shop do it), set my front up to the third notch on my 5100 Bilsteins, and had the same shop do an alignment on the truck. Well after receiving the truck back I noticed a small vibration while driving at speeds of 60 mph and higher. Not a big deal at the time. There was no shaking/vibration as long as I was below 55 mph.

Then, a bit more driving and closer to 70 mph the truck starts to shake--not violently but enough to cause concern. That shaking would continue even after slowing down until I got closer to 50 mph.

Not liking the shaking that's happening, I took it back to the shop today to have them look at it. They called me just now saying that it was the drive-train that was causing the shake due to the front diff drop that was put in. Basically because the angles of the front diff to the back diff are different from stock that is causing the truck to shake at high speeds. And more so there wasn't anything they could do about it.

So now, for those that may know better or have experienced this, what should I do? Is the shop right? Is the shaking/vibration due to the above, and is there really anything I can do about it? Should I remove the diff drop and put the Bilsteins back down to the 2nd notch (to avoid CV axle issues)?

The more aggressive shaking I felt didn't feel "safe" or something that I'm comfortable with the truck doing at high speeds. I also drive this truck to/from work and reach 70 mph daily, not to mention use this truck for cruising up into the mountains at those speeds if not faster.

Any advise would be greatly appreciated!!

 

[00_4runner]

Had this same exact problem after I installed my coilovers, the problem is exactly what you think. However more so that your suspension geometry is too far from stock. Driveline angles are just too great and the only way to fix it, from what I have read, is a carrier bearing drop and a one piece driveshaft. I fixed it simply by lowering the coilovers, all the vibration disappeared right away. Lower the front back down a notch and your problem should be solved.

 

[PitbullRescuer]

I would think you could cure it just by bringing the cols back down one notch. Not so sure you would need to pull the diff drop out of it.

 

[CoMarc]

Thanks for the replies! I'm going to have to look at my options. I didn't care for the stance on the second notch with the LC coils, so maybe I should look at swapping them out with some 890s...

Thanks again!

 

[Beach Runner]

I've had this same problem since I first installed my lift. I had the shop that mounted my tires re-check the balance and I've taken it back to Firestone to have the alignment looked at a second time. After all this I still feel a vibration in the steering wheel around 60mph and it's starting to wear the outter edge of my new tires. I love the stance it has now, but I may lower the Bilstein's one perch to see if that helps.

 

[Baja Runner]

Weird, I am noticing the same issues this week...

I just went and replaced the ball joints, and inner and outer tie rods. I ended up jacking up my front about .25-.5" and now I have the vibes at 60+, even after an alignment.

 

[Beach Runner]

That's ironic, I just picked up ITRE's, OTRE's, and LBJ's this morning for the install Saturday. Guess I'll go back and rent the spring compressor while I'm at it. It's gonna be a long day!

 

[opie74]

I believe its due to working all the caster out of the front end. The place I had my alignment done said the caster is not adjustable. The FSM says otherwise, but granted there is not much caster adjustment to be had.

I tamed all my vibes by replacing everything in the front end as it seem its all cumulative. I am going to have another alignment done and see if they can get some of the caster back. If not, Im going to look into aftermarket UCA's.

 

[Baja Runner]

Looking at the alignment printout, yes, there is not enough caster angle.

I'm curious though... say you lifted the rear up a bit, would that put the front caster back? hmm...

 

[opie74]

Looking at the alignment printout, yes, there is not enough caster angle.

I'm curious though... say you lifted the rear up a bit, would that put the front caster back? hmm...

No. The only way to do it is the get the upper mounting location rearward from the lower. Lifting the rear would have the opposite of the desired....

 

[1985taylor1925]

This thread makes me laugh because Ive replaced basically my entire front end and had like 6 balances and 3 alignments in the past 1.5 years, and I still cant get rid of my highway vibration. The best it has felt was after I had discount tires put on new tires and balance them. They did a good job. But after that I got the Tacoma wheels, which require wheel spacers because of the backspacing. Discount tire wont do any work on a vehicle with wheel spacers and Toyota cant seem to get the balance right.

 

[opie74]

This thread makes me laugh because Ive replaced basically my entire front end and had like 6 balances and 3 alignments in the past 1.5 years, and I still cant get rid of my highway vibration. The best it has felt was after I had discount tires put on new tires and balance them. They did a good job. But after that I got the Tacoma wheels, which require wheel spacers because of the backspacing. Discount tire wont do any work on a vehicle with wheel spacers and Toyota cant seem to get the balance right.

Replacing front end bits will not restore caster angle. Not enough positive caster will make the front end feel loose.

Caster angle - Wikipedia, the free encyclopedia

 

[Baja Runner]

No. The only way to do it is the get the upper mounting location rearward from the lower. Lifting the rear would have the opposite of the desired....

Actually, our trucks are meant to have positive caster, not negative. I thought about it more, and rotating the rear up would give back some positive caster... But how much, I dont know.

 

[opie74]

Actually, our trucks are meant to have positive caster, not negative. I thought about it more, and rotating the rear up would give back some positive caster... But how much, I dont know.

And positive caster is attained by tilting the upper mounting point rearward of the lower mounting point. Lifting the rear of the vehicle would equate to a move away from positive caster.

 

[1985taylor1925]

And positive caster is attained by tilting the upper mounting point rearward of the lower mounting point. Lifting the rear of the vehicle would equate to a move away from positive caster.

Ya. So caster must be based on the position of the steering rack also right? I.e you would produce more positive caster if you moved the steering rack slightly forward, in that you would be producing the same effect as increasing the angle of the axis line between top and bottom ball joints by moving the top ball joint further back?

 

[Baja Runner]

First positive caster is opposite than what I was thinking. Just type it into google, duh.

No, the steering rack has no input. IT is the angle of the line that goes through the ball joints.

I'm still uncertain if the caster issue is really causing the vibes. I'm thinking it might be the large angle on the half shafts/CV's... I wish I had the opportunity to take them out and try.

 

[1985taylor1925]

Ya. So caster must be based on the position of the steering rack also right? I.e you would produce more positive caster if you moved the steering rack slightly forward, in that you would be producing the same effect as increasing the angle of the axis line between top and bottom ball joints by moving the top ball joint further back?

Scratch this. I just did some research and think I understand it pretty well. So if you lifted the front end and back end the same amount, caster should be equal to stock height because youre not changing the axis angle. Youre just raising it. If you lift the front too high, you gain positive caster. If you lift the rear to high, obviously you decrease caster.

This is a much better article than wikipedia by the way, and it states that most vehicles are not that sensitive to slight changes in caster, as long as it is equal on both sides.

Caster, Camber, Toe

 

[1985taylor1925]

First positive caster is opposite than what I was thinking. Just type it into google, duh.

No, the steering rack has no input. IT is the angle of the line that goes through the ball joints.

I'm still uncertain if the caster issue is really causing the vibes. I'm thinking it might be the large angle on the half shafts/CV's... I wish I had the opportunity to take them out and try.

Agreed. Check out the link I just posted. Its the most detailed discription Ive found. In fact a higher front lift would create more positive caster, which would actually help stabalize the front tires according to that article. Hence the reason they increase caster on race cars. So if the lift is the cause of vibrations, then like you said its due to the angle of the cv's. And the steering rack would affect foot and toe, not caster

 

[CoMarc]

So if the lift is the cause of vibrations, then like you said its due to the angle of the cv's...

So, how do we decrease the angle of the CVs to get rid of the vibration without loosing our lift? I figured that's what the Diff drop was supposed to do.

 

[1985taylor1925]

So, how do we decrease the angle of the CVs to get rid of the vibration without loosing our lift? I figured that's what the Diff drop was supposed to do.

The diff drop is really all you can do. You mentioned in the first post that the shop said the difference in angles of the front and rear driveshaft was the cause. Ive never heard that before and honestly dont know anything about it. But they could be right. Personally what I would do is take off the diff drop and lower the front down to around 2" of lift. Thats exactly how my truck is set up now. Tundra setup with no diff drop.