kaz2000xjsport

So after a 4.5 lift (Rough country with new control arms and rear springs) is an SYE necessary? I'm doing the T-case drop but what else is needed?

PetrolHead

Depends. You'll probably be fine with the t-case drop, but I went with the SYE because you don't lose ground clearance and seemed like a more permanent solution. T-case drops are really just band-aids. Mine has a 4.5" lift and I didn't really get many vibes, but I developed this sort of grinding off-throttle. SYE fixed that right up, and it's really not hard to install. There's a thread on here where you can pick one up for $150 shipped, that's what I did and it's the way to go for sure.

Zack92MJ

I'm broke high school kid. I have a tcase drop and shims and do just fine.

SoCal2kXJ

Which rear axle do you have? If its the 8.25 you will probably need a SYE. I needed one with only a 3" lift. Don't waste your time the the TC drop kit. Just do the SYE, maybe shim the rear axle and be done with it.

kaz2000xjsport

lol same

I do have an 8.25

Somebody have that thread with the SYE for 150?

Zack92MJ

I have a 8.25 with 4.5" of lift, I call complete bull on needing an SYE. If you go down there and look the driveshaft on my jeep is maybe 3/16th" - 1/4th" father out than what it was stock.

But yes an SYE will fix the problem, 100% no matter what. But my tcase drop was 5 bucks and the shims were given to me so I'm not worried about it one bit. I'll save the $200.

just my .01

Metmknice

USername of the person with the AA HD SYE is harleys.. search for the name.

SoCal2kXJ

You must be one of the luckey ones. Most later model XJs with the longer TC output shaft and the longer pinion 8.25 need a SYE because of the tighter driveshaft angle.

jeepheep1

My Senior Bio teacher and good frirnd (just graduated ) has 4.5" on his 96 and is the reason I'm not hard pressed on a SYE. Said no vibes at all. However, a driveline upgrade could never hurt, especially a SYE on a lifted vehicle. Looking forward to ditching my TC drop when money allows..

dogger15

It's not just getting away with no sye for a dd. when you go wheeling on certain trails your axle will drop far enough down that your slip yoke can slide off your output shaft on the tcase. If this happens then good luck to you atleast get a hnt for $100 and snag a for ds out of an xj from the jy. For my jb conversion sye cost a little over $200 after shipping plus another $20 for a front ds. Some may think I'm an a hole for this next comment about to make but in all honesty if you are complaining about having no money for your jeep then find another hobby / mode of transportation that you can afford to do.

jeepheep1

All things come in time good sir. Personally, I'm buying everything bit by bit. It's not a matter of complaining about money for most of us, we all love our Jeeps, but I don't think any of us have the money to buy all the mods we want right out the door.. Right? However, I completely agree with your comments about the SYE! I can't stand people who neglect the obvious and complain when they're stranded.

thebe001

Drive shaft falling off when wheeling possible but now likely. There is no question a SYE is the best option however its not the only option. If you are on a budget I would not jump to put on an SYE, start with a T-case drop first it may solve your problem, you should be able to make one or under $10 + some time. Chances are you will still have some vibes but if they are minor you may be willing to live with them until you can upgrade to a SYE. I have a 4" lift on my 99 XJ with only a home made T-case drop and I have virtually no vibes.

Zack92MJ

I couldnt agree more with the last two posts.

Lyon

To the OP...

Do the SYE as soon as you can. Get an angle finder and set up the rear axle correctly with the correct shims. You can't just buy a set of shims and throw them in there. It needs to be accurate. SYE's alone do not "take care of" vibrations. They help the driveline by adding one more U-joint to the equation to LESSEN the vibrations and stress on the drive-shaft itself. The pinion being inline or 1* lower to allow for any axle wrap is key for getting rid of vibes totally.
I started out with a 3 inch RC lift with a TC drop. Ran that for about a year until I went up to 4.5 inches. I ran the stock shaft for about 2 days because it vibrated like a (*&^#!. Mine is a 99. Doing the TC drop eventually led to other problems for me which I found out a while later. The transmount was crushed on the back side because it changed the angle of the drive train. It also stretched the motor mounts because it actually pulls the engine back slightly when the trans it dropped. So they went bad. The TC drops also changes the front driveshaft angle making it worse because the CV part of the shaft is now pointed against the angle of the driveshaft. This is overlooked by almost everyone who does them. TC drops don't help U-joint life by enough to warrant to keep it. That's why it's a temporary fix.
Could you run the stock shaft? Yes, by all means. Will it cost you more in the long run not doing the SYE? Absolutely. Would you rather pay $150 for a SYE or risk blowing U-joints every few weeks and possibly the output shaft of the trans and then have to get it then anyway?
People claim "I've run a TC drop for 100 years and I have no problems!" They have problems, they just don't have them immediately. And then complain when all this other stuff is going wrong with the Jeep when it wasn't set up "correctly"
A driveline that has "virtually no vibes" is a driveline WITH vibes. Period. Which means something is not right. Vibes will eventually either ruin U-joints, slip splines (On CV style shafts), pinion bearings and transmission output bearings over time. For a vehicle that sees the road alot, these should be taken care of to eliminate problems. If it's only for the trails, normally you're not going fast enough to feel them.

Check out this site. Scroll down to the bottom right of the page where it says TECH INFORMATIONm then click Geometry Drivelines 101 and read up. This should clear some things up. http://www.4xshaft.com/
Good luck on your build.

bheath

so every jeep with a TC drop has or is going to have problems? interesting. i better sell mine then, maybe buy a toyota.

besides since i've had it for +4 years, w/ tc drop, its time to move on. the problems are gonna be here any minute now... i just know it...