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Discussion Starter · #1 ·
I recently installed a 2" lift and now I have vibes around 45+ mph especially on acceleration. Its more like humming/vibration feeling. I lowered my transfer case skid about 1/2"-3/4" and still not making a difference. I really don't want to buy a SYE beings how thats why I tried to stay around smaller size lift.
 

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I want to say the case drop pucks I got with my 3 inch lift were over an inch...might just have to keep dropping it a bit more to get it out.

I ended up getting an sye though. When you drop the t-case, it messes with the stock alignment and makes shifting a pain.
 

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Another option is a motor mount lift. When I reached 2.5" I ended up with vibs. Being on 31's and not wanting to lose valuable belly clearance, I added JKS motor mount blocks which eliminated the vibs.
 

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Discussion Starter · #4 ·
I want to say the case drop pucks I got with my 3 inch lift were over an inch...might just have to keep dropping it a bit more to get it out.

I ended up getting an sye though. When you drop the t-case, it messes with the stock alignment and makes shifting a pain.
That moment when you found out that a BUDGET boost isn't so budget.:jawdrop:
 

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Yeah the shop told me shocks, springs, and the case drop was all I needed.

Turns out you need sye, rear drive shaft, upper adjustable rear control arms, adjustable track bars, bracket for track bar after sye, and longer sway bar links if you want to do it right.
 

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I have a 2" SL as well and I have vibes. Leanings towards the MML to hopefully fix that issue.
 

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I have a 2" SL as well and I have vibes. Leanings towards the MML to hopefully fix that issue.
You're still dealing with that? The JKS blocks worked for mine. It was tight not having a body lift but certainly doable. No interference issues at all afterwards and best of all, no more vibrations.
 

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First thing you want to do is figure out if it's front or rear. Bad u-joints or centering ball, or worn slip yokes, make sure the slip yoke aren't frozen or very stiff to slide. If all that checks out then adjustable upper control arms will fix it even without a SYE. The little bit you'll have to rotate the pinion won't require any kind of TB bracket or adjustable TB.
 
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yah now its either couple adjustable CA"s on the rear to help hold that angle or MML. I also have a 2" from PO and it had pulsing vibes at highway speed in high gear ..........MML erased it
do as mudbug suggests and check everything well the trans drop shoulda made u right
 

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I'm sure either would fix it.

With a MML there are other things to consider like fan to shroud clearance, trans to tub clearance, shifter function, potential exhaust issues down the road.

With CA's IMO is a win win, non of the above things to consider, better CA's with new bushings, ability to fine tune the pinion angle.

With an angle finder and less than a couple hours of work in the driveway with simple hand tools and it's a done deal.
 

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Changing the rear pinion angle is not the answer with the stock single-cardan driveshaft. In fact, don't do it. The pinion angle needs to remain parallel to the tcase output shaft angle as the factory set it.

You say you dropped the tcase 1/2-3/4". That's normally enough for a 2" SL, if that's what you actually ended up with. But if you stacked washers between the frame and the skidplate, you didn't get as much drop as the washers were tall. Like if you stacked 1/2" of washers, you only actually got probably less than 1/4" of drop due to the indentation the stack of washers sits in.

How much actual tcase skidplate drop did you get, measuring the gap between it and the frame? You may just need to add a little more drop. My first TJ lift was also 2" and 5/8" of tcase drop from perhaps 7/8" stacks of washers completely eliminated the vibrations.

Here's a quick question... did a previous owner install cam bolts on the upper rear control arms at the frame side? It almost looks like the rear pinion angle is a tad high which would explain most of the vibrations coming during acceleration.
 

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I did a mml when I did my 2inch lift and had no vibes. Only after I installed a new t/c skid,which wasent flat, but flatter than stock did I have vibes.
 

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Changing the rear pinion angle is not the answer with the stock single-cardan driveshaft. In fact, don't do it. The pinion angle needs to remain parallel to the tcase output shaft angle as the factory set it.
Then please tell how you suggest setting pinion angle on a lifted Jeep with a single cardon shaft. When the pinion angle does not match the T-case output?

It worked just fine on my 4" lift used in conjunction with a t-case drop to bring the pinion up 3 degrees to match the T-case output. No, I did not want to add more drop an inch is more than I care for in the first place.

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This is a temporary solution for me as the toy budget has been depleted. A SYE and rear driveline in order to remove the t-case drop along with the other mods that are planned for the t-case isn't in the budget right now. If someone is fine with a t-case drop then I see no reason that this couldn't be a permanent fix.
 

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Then please tell how you suggest setting pinion angle on a lifted Jeep with a single cardon shaft. When the pinion angle does not match the T-case output?

It worked just fine on my 4" lift used in conjunction with a t-case drop to bring the pinion up 3 degrees to match the T-case output. No, I did not want to add more drop an inch is more than I care for in the first place.
When you have a dramatic change in the tcase output shaft angle from trying to cope with things like your 4" SL and stock driveshaft, then yes using adjustable length arms to change the pinion angle to match it is only way to go. But with the OP's 2" suspension lift, he should not have a dramatic change in the tcase output shaft angle like you did with your 4" SL.
 

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You're right on the 2" lift shouldn't have bad angles..... If the u joints and everything about the shafts are in good order the next step would be measuring the angles of the pinion and output. That and only that will determine which direction the next adjustment should be. To suggest jumping into a MML or dropping the t-case more is a bit advanced. Until the OP has done a thorough inspection and determined the angles.
 

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After I did my CV driveshaft and adj uppers I got my angle pretty close to perfect. My yoke is 1 deg less than the dfriveshaft.

 

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Lots of personal experience with installing MANY 2" suspension lifts (probably well over 100) on TJs for a living. I used to have them installed all the time for my half-dozen Jeep dealership customers selling lifted Jeeps, along with 4" SLs too) says the vibes from 2" lifts are easily cured by between 1/2" and 3/4" of tcase drop. Are there other ways to cure the vibes? Yes (1" MMLs, SYE kits etc.) but they cost more $$$ and aren't as easily installed.

He just wants a simple low cost 2" SL without vibrations, there's no need to jump into things like having him measure angles. This is a such a common issue that there's no need to reinvent the wheel here so far as having him verify angles. :)
 

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An old carpenters adage the works well in my applications. "Measure twice, cut once" If someone want's to know what to do and what direction to go would be measure. A simple angle finder costs less than $10 and will confirm if the angles are even bad. Could be something else causing the vibes. Hate to have the OP spend a money on things that may not help. Kinda like throwing parts at something that hasn't been properly diagnosed that gets expensive after a while.
 

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An old carpenters adage the works well in my applications. "Measure twice, cut once" If someone want's to know what to do and what direction to go would be measure. A simple angle finder costs less than $10 and will confirm if the angles are even bad. Could be something else causing the vibes. Hate to have the OP spend a money on things that may not help. Kinda like throwing parts at something that hasn't been properly diagnosed that gets expensive after a while.
Whatever you say. I only did it for a living having worked for Transamerica who owns 4Wheel parts, ProComp, Rubicon Express, etc. and have lots of personal experience on having installed over a hundred 2" budget boost lifts (plus as many 4" lifts) for very fussy and very budget-conscious new Jeep dealers.

In fact I taught a lot of my shop techs how to troubleshoot and cure drivetrain vibrations and how to properly measure the angles. Not many understood the subject and fewer yet understood the angular differences required between single and double-cardan (CV) driveshafts. Most thought they had to jack around with the rear pinion angles on even minor 2" lifts. They eventually understood and I had a lot fewer vibration issues with the Jeeps and trucks they were delivering to my customers.
 
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