New lift vibration issue's

[XJdunnz]

Put on new RC 2.5" lift and 1/2" boomerang shackles the lift measured out around 4" when done, I dropped the t case 1" but still having vibration issues at around 45 mph and slower also having shaking when stopping.

Do I need to drop the t case a little bit more?

 

[69jeepcj]

this is on a wrangler right? I have read that rear driveshaft vibration is a problem with the YJ wranglers, I read that some even left the factory with this problem. when lifted this needs addressed. Did your lift come with rear spring shims?? If so and you droped the tcase down, you may want to look into a slip yoke eliminator. Im not positive if it will help, but seems I read that it helps rear vibration as wel as put a ujoint on the tcase side of the driveshaft. If your lift didnt come with shims for the rear springs, you probably need to get some, they will lessen the ujoint angle some more without droping the case further. I would not drop the case anymore.

 

[Bounty__Hunter]

Might be too much TC drop as 1" is generally used with a 4" kit. Get an angle finder and make sure the rear pinion is parallel with the transfer case output.

 

[69jeepcj]

YES! that is true. I overlooked that it is a 2 1/2" lift. bounty hunter is correct that a tcase drop usualy is not required for a 2", and is posible that may be whats actually causing you vibe.

 

[XJdunnz]

Thanx guys, the lift is a 2.5 and the shackles gave an additional 1/2" of lift but the lift measured out around 4" when finished. The shims for rear will be my next find if I can't get the vibration to stop.

I'm also looking into getting a new front track bar the old one is causing the shackles to flex toward the drivers side due to being a little to short now. I had this exact lift on my last yj without issues but I dropped the t case 1 1/4" on it.

 

[Bounty__Hunter]

What size tires are those?

It's all speculation and just throwing parts at it until you actually check the driveline angles.

 

[XJdunnz]

What size tires are those?

It's all speculation and just throwing parts at it until you actually check the driveline angles.

The angles look pretty good that's why I'm so confused tires are, 265 75 r16

 

[superj]

unhook the trac bar. you don;t need that. (unless its required for safety inspections, then you can put it back on for that)

 

[Bounty__Hunter]

The angles look pretty good that's why I'm so confused tires are, 265 75 r16

That's equivalent to a 31" or 32" tire, and the pic looks like a solid 2.5" lift. I'd recommend removing the transfer case drop and checking the slip-yoke at the transfer case tailshaft to make sure there's enough spline engaged on the tailshaft. You really shouldn't have a t-case drop on there. If anything, maybe a 1/2" drop at most.

Can you post a pic of your rear driveshaft angles? Get the entire driveshaft and yokes from the side.

Your angles should be set up like this:

 

[XJdunnz]

Thanx I will get some shots later when I'm around the jeep. I used this same lift on my last yj with stock shackles and had to use a little over an 1" t case drop to stop the grinding and vibration and it preformed well, this lift is a tad bit higher due to the boomerang shackles adding an additional 1/2" of lift

The yj is also an automatic so not sure if this has an affect on dropping the t case or not this my second yj and second lift kit the first was a manual.

Thanx to everyone for all the info

 

[jfrabat]

Just in case, check also your U-Joints... It IS possible that the vibes are not coming from the lift.

 

[XJdunnz]

That's equivalent to a 31" or 32" tire, and the pic looks like a solid 2.5" lift. I'd recommend removing the transfer case drop and checking the slip-yoke at the transfer case tailshaft to make sure there's enough spline engaged on the tailshaft. You really shouldn't have a t-case drop on there. If anything, maybe a 1/2" drop at most.

Can you post a pic of your rear driveshaft angles? Get the entire driveshaft and yokes from the side.

Your angles should be set up like this:

Here's the pic of my angels, tell me what you think. Thanx

 

[Jester32]

Pinion is to high up by the looks of it.

 

[Jester32]

The front and rear angles should be almost the same. Called cancelation angle.

 

[rock316]

need to lower your pinion and a longer drive shaft

 

[jfrabat]

I was about to say it looks fine, but then I remembered you dont have a SYE... You defenetly have an angle problem as described by Jester. Not sure if the TC Drop kit is the culprit, though, as I don't see removing it will cause the vibes to go away. Are you using degree shims or new shackles or anything else that may be changing the pinion angle?

 

[XJdunnz]

I was about to say it looks fine, but then I remembered you dont have a SYE... You defenetly have an angle problem as described by Jester. Not sure if the TC Drop kit is the culprit, though, as I don't see removing it will cause the vibes to go away. Are you using degree shims or new shackles or anything else that may be changing the pinion angle?

Not using degree shims but will be looking into them. The shackles are new as well as the lift I put on some boomerang shackles that add 1/2" of lift.

 

[jfrabat]

I would stay away from shims... Most of them are aluminum, hich can crack, and that is just not good! Also, it seems your difference is just too much for them anyway. I would buy new perches and correct the angle the right way (welding obviously is involved here).

 

[HB Jeeper]

I had the same issue on my 95 Wrangler after adding a 4" lift to it. The slip yolk eliminator was the fix. If you do not add the SLE, then you will have u-joint issues.

 

[Jester32]

I run shims steel ones that way when I do my sye I can change it easy shims won't crack unless improperly installed. I would look after that vibe ASAP though. Hard on the diff the t case and your teeth lol