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Discussion Starter · #1 ·
Well I installed the Fabtech 4.5" lift this weekend went and had the truck aligned and I'm getting a vibration in the front driveshaft at around 65-75. Took the front driveshaft out, no more vibration. Is there any solution to this? Seems like alot of people have this problem. Would the warranty cover this by chance?
 

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Discussion Starter · #3 ·
How do I adjust it?
 

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Discussion Starter · #4 ·
Well I took it to the dealer and they replaced the entire front driveshaft assembly. Still have the same vibration, but if I take the driveshaft out it stops. Called Fabtech, guy said put around 800-1000 miles on the lift to let the springs settle and more than likely it will cure the vibration. The springs will settle what maybe a 1/2"? Sounds like BS to me but I dont know. Gonna take it back to the dealer and see what else they can replace I guess. Warranty runs out in July so I want to get this fixed before then. Any ideas on this I know someone else has had this problem.
 

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pinion angle needs adjusted like Smoker said. Its the adjustment on the lower control arm. loosen the nut and make an adjustment to raise the pinion up a little bit at a time.
 

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Could also be ready for some u joints the stock ones ain't so good.
 

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if you go setting the pinion angle too far back to alighn the drive shaft you will put too much caster in the front end you need to index you transfer case what you do is clock it down so the front drive shaft has room for the ujoint to move freely. you can look into a transfer case indexing ring or have a cv style joint put on the drive shaft end at the transfer case will cost you from around $300 or so depending who does it. or an indexing ring might be cheaper
 

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How bad is the vibration? How often are you running 75? Is it something you can live with, or is it unsafe?

You know the ujoints are bad and you are complaining about undiagnosed vibrations. Go fix your ujoints today.

Indexing ring is a quick easy fix. I am not sure how the crossmembers work on a 3rd gen, but they have to be notched on a 2nd gen.

Does the driveshaft spin all the time on 3rd gens? Assuming it does -- you could buy a conversion to put lockouts on it.
 

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Putting lock outs on would be the ticket and I want to do that with mine as well but not everyone can drop $2k for the kit to do it.
 

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Discussion Starter · #10 ·
The vibration is not terrible but it annoys me, I could live with it but I probably wont. The ujoints are not bad, the dealer replaced the entire front driveshaft ujoints and all. The pinion angle is what I figured was causing it but I was reluctant to just start cranking on the cams after I just spend $100 on an alignment, which I'll probably have to do again once I adjust the pinion angle. I've heard of the indexing ring may try that where is the best place to get one? I dont know anyone around here that would put a cv style joint on the driveshaft. I will check the driveline shops around here and see if they could do it. Which is the better fix?
 

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Discussion Starter · #12 ·
Fabtech sent me a transmission drop bracket that supposed to correct the vibration. Seems to me like dropping the tranny would stress other things like motor mounts etc. Anybody have any experience with this? The vibration is not terrible anymore with the new driveshaft, but I hate to put this bracket on and cause further problems.
 

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I have had the same vibration since I installed my 4.5" lift a month or so back. I just adjusted my castor with the lower control arm bolts/eccentrics till I got the front axle pinion at the same angle as the front drive shaft. Voila! the vibration went away. Give it a try...
 

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the springs will settle, thats why most installers will tell you to drive the truck regardless for 500 miles and then come back
 

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I just had the same problem with mine. I took it up to joint and clutch in Indy and they put a longer shaft in it for me. It cost 110 dollars. When you take it in to get a new shaft put it you need to know the face to face measurements from output shaft of transfer case to input shaft of front differential. Be sure and measure from the top to the top and also measure from the bottom to bottom. They will probably be different the top measurement being longer.
 

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Discussion Starter · #16 ·
It has gotten better with the new driveshaft and the more miles I put on it. Just found out there is a driver side coil and a passenger side coil which it said nothing about in the installation directions. Of course I have them swapped around because I didnt know anything about it till I called Fabtech. They said one side of the truck is heavier than the other. Measured the truck on both sides and its the same though.
 

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dont adjust your pinion angle,it will throw off the caster and most likely have death wobble.Just put the tranny drop bracket in and it will solve your problem.I have had a truck with a tranny drop bracket with over 40000 miles on the lift with no problem
 

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I just started getting the problem with vibration, but my front shaft threw the weight that's typically welded on. I've got mine set up with the dealer to get it fixed on Wednesday, so that should fix it.

Check your front shaft to see if there is a shiny spot where a weight once was, but is now gone.
 

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I had the same thing happen and they replaced the shaft with a custom high angle shaft and its been perfect ever since. They suggested to either put a high angle shaft on or to drop the transfer case and i incisted on leaving the transfer case alone so i wouldnt have to add another link.
 

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A high angle correct length drive shaft sounds like the ticket!
 
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