T-case vibe.... 98TJ...4" LIFT

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dick_wilderness

New member
I installed a 4" superlift, with Tcase lowering bracket, and I'm still getting some shimmy on the tcase side of the rear drive shaft. It sounds like the Tcase is gonna fall out when I first accelerate.

I'm probably looking at a SYE and drive shaft, huh?

By the way if anybody knows any 4wheel drive specialists (mechanic) in SE PA, hook me up with a website or phone #

thanx
 

The TC drop usually solves the vibes at only 4" of lift. Did the kit come with longer rear lower control arms?

Sounds to me like it's a pinion angle issue, like the pinion could stand to be pointed up a little bit.
 
YA, sounds like you need adjustable control arms. adjust the pinion angle to 13 degree's, right?? this will solve some of the vibs, but the SYE is the only way to get that close to stock feeling!
 
Only came with front lower controls arms.

Oh well, just another 1000$ in parts right? I can't say I was blind to the "$$$" factor of jeep ownership.

If I'm not mistaken SYE = longer driveshaft?

PS. Is pinion angle adjustment difficult?
 

SYE= shorter transfercase output and LONGER driveshaft
 
I found a good deal @ Tom Woods Driveshaft's. Comes with the heavy duty output shaft SYE kit, and rear CV shaft for 525$. That includes shipping.
 

You'll need to point the pinion directly at the TC output with a SYE, so you'll likely need adj. control arms either way.
 
btw they do make an adjustable cam style bolt for the rear to give you some adjustment to the rear pinion to reduce drivling vibration. They only cost about $40. Just a thought. Also I have installed alot of the 4" kits and never had a bad vibration after. This includes Skyjacker and superlift. There kits are very much the same. I would check your ujoints and make sure that they are all good, also you can losen up your transmission mount on the skid plate, put the truck in gear and move it a hair, then tight everything back up. Sometime there is a little binding in the transmission mount after installation and this will allow it move into place. Just don't go driving it losened.
 

Thats funny my mechanic said it looked like the transmission mounts at first. The vibration isn't terrible, but after a while its gettin to me and I feel like somthing could break???? If i could avoid the SYE it would be cool. I'll run it by him again. But I also have heard that any lift over 3.5 inches will require SYE to get that stock feel to the drivetrain. I am not very mechanically inclined, though (yet).

PS. ecor if you know any good 4x4 shops down by philly let me know.

thanks
 
ecor said:
also you can losen up your transmission mount on the skid plate, put the truck in gear and move it a hair, then tight everything back up. Sometime there is a little binding in the transmission mount after installation and this will allow it move into place. Just don't go driving it losened.
Click to expand...

My BDS kit's installation insturctions:

10. Drive vehicle to allow all components to center in
their mounts. Torque the two remaining transfer
case mount bolts to specifications.

11. This procedure should insure no drive line
vibration. Alignment angles will be affected by
installation of a suspension lift. We suggest an
alignment be performed to ensure proper handling
and tire wear.
Click to expand...
Drive it gently around the block and then retighten them.
 
I nver figuredd out why they put that in the YJ instructions and not in the TJ instructions. We do it on all of them now. We have found that it works well. I am also not going to lie, you will have some vibration. It will not totally go away. I know ;lots of people that Have driven for years with the slight vibration and after a while say they don't even notice it anymore. You will go through more u joints though. You may also want to go with the cam bolt kit I looked them up they are actually only $30.00
 

Four wheelers for sale

If i do go SYE route, do i definatley need rear adj lower controlarms?

Or just that thing ecor was saying?
 
If ecor says the cam kit will line the pinion up with the TC output, that's all you need. But like I said, i would use longer lower control arms on any lift 4" and up. Just personal preference, helps minimize tire jacking and death wobble.
 
The cam kit wil help bring it up. If you change just the lowers it will push the pinion down farther. The longer lower trailing arms are 1" longer then stock and the longer uppers are 1" longer. If you just change the lowers and they are longer then you will be pushing the bottome of the axle out and not the top. This will help with your camber and castor in the front but will cause problems in the pinion angle. Some engineers are now saying that the longer arms are just to push the axle forward to recenter the axle in the wheel well. With adjustables you can tweak in a happy medium. This will also bring back some of your flex. The poly bushing non adjustable arms actually take flex away from your vehicle, the arms are limited in twisting.
 

dick, I would try the suggestion of ecor first. I just did a lift on my YJ (december '03) and after the t-case drop, I still had vibes too. I came here and TwistedCopper was the first to tell me about this little trick. My roughcountry instructions didn't include this step either. As soon as I loosened the transmission mount nuts, the drivetrain moved 1/4 to 3/8 of an inch, right off the bat! I left them loose, drove around the block (being sure get left AND right hand turns in). Then parked it on level ground, tightened those badboys up, and TA-DA! The vibes were gone. This is a very important step. Should've been obvious when we dropped the t-case, but didn't occur to us. Live and learn.

C
 
no if you get the SYE kit you don't need new control arms. Tom woods is definately the place to get it too. There are six guy in our group with various kits and the me and one other guy have the tom woods kits. Nothing out there any better and that is really the only thing you can do to get rid of that vibration. It is also definately worth it to get rid of your stock transmission mount and get an agtermarket poly mount!
 
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