so I have about 150 miles on my Icon 4.5" kit. truck drives good on the highway, fine around my house. I was told to see if there is a vibe as I have a CC and I may need the carrier shim kit. nothing I can really feel during normal driving before today. now there is a road a few towns over that has some "bumps" in the road. kind of like where the road was pushed together in one spot and made a hump across the roadway. well....I went over one today at about 50 mph and the truck started to VIOLENTLY shake. I thought a wheel was falling off and i jammed the brakes. got down to 25mph or so and it stopped. hit another one and it started again. came up to a 3rd one and got off the gas to coast over it...same thing. I mean...the truck is litterally jumping around back and forth violentyl and make me pretty nervous...nervous enough to take the lift out. no way can this be related to the carrier not being shimmed can it?? thanks for all your help

 

Sounds like an alignment issue or a loose trac bar, trac bar bracket, etc...

Was everything properly torqued down to spec with the truck on the ground?
Have you retorqued everything since the install?
Did you install the caster cams that came with the lift?

Have you had the truck aligned since the lift?


Lack of carrier bearing shim would give you a slight vibration on take off.

 

i did....i dont have a tq wrench that goes to 369 so I went to 250 and gave it another half a tunr with my right foot.

caster cams???? did not get those....

 

My mistake, the caster cams are on the 2.5" and 7" Icons....brain fart.

I would check the trac bar bracket, make sure the turnbuckle on the trac bar itself it tight (don't go he-man on those little bolts though) and I'm not sure if that is tight enough on the trac bar bolts themselves...

 

I will...gonna go re-tq everything now....hopefully I find osmething easy...

 

In our experience, Icon 4.5" lifts don't wobble unless something is loose (generally related to the trac bar).....so it shouldn't be too hard.

 

everything was to spec. oculdnt check the upper trac bar (369 ft lbs) so I went to 250 and gave it another tug...its all tight

 

Depending on how hard of a tug and with what, that might not be 369ft/lbs.

You may see if a shop in your area (dealer should have one) has a torque wrench that can go to 369 ft/lbs.

Some guys use a big (4' or so) cheater pipe over a breaker bar to tighten them up.

 

when i first put it on it was a half a turn..used my legs to turn it. i guess ill run it by the dealer and see if they will check it for me. no one I know has one that big and 2 buddies own shops...haha

 

Dealer should since Dana 80 pinion nuts require 480 ft/lbs.....but what they should use when installing and what they do use isn't always the same

Or shops that work on big trucks, big tractors, etc... My buddy's work has one that goes to over 2000 ft/lbs (1.5" drive, can be broken down into 3 pieces, fully assembled is 8-9' long )

 

Dang, now that is a torque wrench! I would love to see it.

 

I'll see about getting a picture......used on axles of big log skidders and such, torqued to 3000nm.
Have to have a separate "tool" that is secured inside the wheel to keep the wrench straight/centered since you are 8-9' away from it.

 

I had a problem getting my upper trac bar bolt tight enough. I just put my snap-on 1/2'' impact on it and tightened the CRAP outta it and was all set. One thing to think about, the factory bolt goes in with the head of the bolt towards the front of the truck. If your holding the nut and torquing the bolt it wont be accurate reading. I turned my bola round so I could get my inpact on the nut and really tighten the heck out of it.

 

My truck did the exact same thing with a 6 inch pro comp lift.......... you need to search the "death wobble"........ the solution is simple u need to change you caster angle....
there was a post that told you the recomended specs....... put your lift back on and change your caster abgle and everything will be fine........

 

You're probably right ...

I suspect the root cause is a resonance setup with the steering box fighting the suspension.

Do you have a steering stabilizer on it? And I mean an aftermarket one, not the stock one.