At what point do I need an SYE?

Hi I recently got an XJ and am planning on lifting it 3"-4" using coils and blocks and was wondering will I need an SYE kit? If I will where would be a good place to get one and would the "hack and tap" kit be good? Also what are all the things I will need for a lift that size? I know I'll need the new coils and blocks and brake lines but what other items might I need? Thanks to anyone who helps.

Search . . . and you need to provide more info if you want serious help.

What kind of wheelin'? What size tires ya gonna run? What year XJ?

Generally: an SYE is a wise choice. Blocks are not. Spacers/shackles would be better IMO and a new leaf pack (not AAL) would be best. Hack n' Tap is fine. Long travel shocks would be nice. Trimming, shims, a new driveshaft, and bumpstops may be needed. You might need new gears. New rims? Why not through in a locker if you're regearing. Heck man, it doesn't end w/ the lift . . .

DR

Since you asked about the hack and tap, and I just typed up a response in another thread on this topic, I'll repost it here:

It's a poor design. More a band aid than a fix. Look at any other SYE on the market and you will see that the rear output flange, when tightened down, is sandwiched between the output shaft inner bearing race and the front of the flange. There's a reason for this- splines are not designed to support the forces created by a spinning drive shaft. Mine worked great with 3" lift and 31s, for 2 years. Then the flange became loose on the output shaft, and had to be replaced. At that time I went up to 5.5" lift with 33" tires, and the new flange lasted 6 months. Rather than buy a new flange every 6 months, I called Tom Woods and did it right.

3 years ago I was on this website supporting the RE hack and tap, but now I know better. It's nothing against RE, because everything else I have bought there has been excellent quality and value.

norcal-Ok since you asked it's an 89 ltd 4 door probably gonna run 31-32" tires and it will be trails and mudding at first but who knows I may get into rocks later on.As far as blocks go I was planning on AAL or shackles but the blocks are free and well I do love free. I might end up getting an ARB locker later but for now open should be fine. I'm leaving the stock ugly gold lace rims on it for now (repainting them black though) I think I have 4.10 gears but I'm not sure, it has the tow package if that helps.

Frank- thanks for the info on the hack and tap. If I need it I'll be sure to do it right the first time it's cheaper.

What I really want to know though is will I need to get an SYE or do anything to the drivetrain for a 3-4 inch lift? The reason I ask is I don't really have much money to work with and I don't want to F*&% anything up by cheaping out.

Typically you'll need an SYE over 3". Older XJs are easy to lift than the newer ones, but it would make sense IMO to budget for either a SYE or HnT. FrankBrew has a different, and valid, opinion of the RE HnT. Mine (with a H.A.D. driveshaft) has been perfect . . .

You can try a transfer case drop, shims, SYE, HnT, new driveshaft, front driveshaft, or any combo thereof. I would plan ahead to do something, especially if this is your DD. You don't want to be stuck w/ wicked vibes. Search.... search.... and search.

DR

MarX said:

I think I have 4.10 gears but I'm not sure, it has the tow package if that helps.

Click to expand...

I'd bet you have 3.73 gears....

FWIW, in general when you're asking 'tech' info, it's helpful if you include year, engine, tranny, tc, axles etc. Something like this:

'99/4.0/AW4/231/8.25/HPD30

DR

I lifted my xj with 3.5"and added transfer case drop spacers and still had a vibe so I installed a sye and it solved the problem .

whether im an idiot or not i dont really see a need for one what does it actually do i know what it does but how much does it really improve the driveshaft angle and all that garbage
i have a 4.5"lift with 1.5" teraflex shackles and spacers and dont have an sye kit or a new shaft maybe i should get it i dont know
i dont know what to do first. 1:tires, new gearing, and lockers 2: sye kit new cv driveshaft 3: trail armor ahhhh sooo many parts so little money

If you have zero vibes, then it sounds like your rig is fine. The SYE/driveshaft helps correct pinion angles. These articles may be helpful:

http://www.4x4wire.com/tech/pinionangle/
http://www.off-road.com/jeep/cherokee/98/03_mar/RE_SYE/slip-yoke.html

As for your money, I'd get armor/recovery points, tires to take advantage of the lift (33s), gears and a locker or two.

DR