An SYE (+ new driveshaft) will almost certainly be required to avoid vibes unless you install a tranny/t-case drop (these aren't fool proof) with a 4.5" lift.

JW

 

sye is a great upgrade, it is not only for vibes(it makes it easier to set up the pinion angle for sure), it gets rid of the slip yoke at the trans, and puts the slip travel in the drive shaft with fixed yokes, much better configuration! Necessary? That could go both ways, for me I would not do without one, they don't cost too much money for what you get, and most likely you can use a stock front driveshaft in the back if you find the right length.

 

i'm about to put on my 4.5in long arm kit can i just do the t-case drop? or do i have to have the sye and extended drivelines? or can i just do the t-case drop and then eventually do the sye and the driveline?

 

With RE's 4.5" lift you more than likely get over 5" lift.
I would install a SYE and Shims for sure

 

Thanks for the responses guys. Looks like John will have to go with the SYE. He already ordered the T-Case drop kit and I have some spare shims we are going to use. It seems he wants to try to t-case drop kit and shims first and then if that doesn't work he will be taking your guys advice and add the SYE and cv drive shaft. Again, thanks for the advice.

 

Be careful using shims and the drop. With the single cardan stock driveshaft you want the pinion and t-case output to be parallel, where with the SYE and double cardan shaft you want the pinion pointed at the output.

 

The answer is still most likely yes. You may be able to get away with a transfer case drop and shim to the ideal angles, but there's a good chance you will have vibration and you will also be pulling the driveshaft pretty far out on the slip yoke. At 4.5" your best bet is a SYE.

 

I would say yes, I put a 4" lift on and got a new HD shaft from Woody's.


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I installed a RC 4.5" lift kit and 33s tires on my 84 Cherokee I did not mess with the driveshafts since I was planning to soon upgrade axles, no driveshaft problems at all, now that I am upgrading the axles I will upgrade the driveshafts as well.

 

I'm no expert , but I am researching the same issues. Dana 44 or 8.25 makes the angle greater between the Trans Case and rear end due to the rear end housing being longer than a Dana 35. The distance from output shaft on Transfer case to Rear end on your setup is shorter than an older XJ I have come to believe through research.

I am about to do a RE 3.5 lift and also have a 8.25 rear end, If I had a D35 I would not need a SYE and TC drop would probably work. lots of people ask about if they need a SYE and some people say it really depends on your XJ. It really depends on your parts actually.

Here is a good one , Anyone with a 8.25 or D44 231 TC get theirs to work without a SYE ? with reasonable TC drop ?

 

I'm no expert , but I am researching the same issues. Dana 44 or 8.25 makes the angle greater between the Trans Case and rear end due to the rear end housing being longer than a Dana 35. The distance from output shaft on Transfer case to Rear end on your setup is shorter than an older XJ I have come to believe through research.

I am about to do a RE 3.5 lift and also have a 8.25 rear end, If I had a D35 I would not need a SYE and TC drop would probably work. lots of people ask about if they need a SYE and some people say it really depends on your XJ. It really depends on your parts actually.

Here is a good one , Anyone with a 8.25 or D44 231 TC get theirs to work without a SYE ? with reasonable TC drop ?

It's based on your XJ, not your parts. The parts will change things slightly, but not enough to make a significant difference. For example, if your driveshaft is 29" long and stock, axle yoke is 3" below the transfer case output, you would be at an angle of ~ 6*. If you do a 3.5" lift, now the yoke is 6.5" below the output shaft and you have an angle of ~ 13*. If the d35 has a shorter nose by 1", you could have a 30" long driveshaft. At 3.5" of suspension lift your angle would be ~ 12.5* instead of 13*. Not much of a difference.

These numbers are all made up, but should be a decent representation. My point is that your lift height will have a lot more to do with the angles than your physical drivetrain components unless you have a d35, rear stretch, and a manual transmission or something, each of which would contribute to a longer driveshaft.

An actual example is that my 2 door 5 speed XJ with the Chrysler 8.25 had 6.5" of lift in the rear with a 1" transfer case drop and ran the stock rear driveshaft with no issues whatsoever. Ran on the highway at 75 mph smooth as butter. My roommates 2wd XJ with the crazy long rear driveshaft got a vibration with a 2" budget boost, even with good u joints. Some Jeeps just handle the changes better than others.

 

Another factor, if the drive shafts are not perfectly balanced or a U joint is aged or loose is the Gear Ratio , I used to have a 67 Chevelle on the road and went from a 2.73 rear end gear to a 3.73 gear , that made my drive shaft spin about 1/3 quicker may not sound like a big deal but I went from having no vibrations to not being able to see straight.

What I'm saying is some XJ's drive shafts spin at a speed out of alignment and some spin faster due to different gear ratios, same alignment with a different ratio may cause big differences in vibrations. may mostly apply to the 4 cylinders came with higher gear ratios ?

 

I recommend checking out Tom Woods' website they have some diagrams on how to measure the distances and angles between t-case and axle. You can always call them too.


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If it's any help, the V8 WJ 4x4 front shaft is a few inches longer than the XJ one, and the I6 WJ slightly longer than the XJ. Both run the same u joints as the XJ rear stock. I run a V8 WJ shaft with my Rough country/omix ada/several other brands that re-box the damn part SYE. Fit well with my 8.25 and later 8.8. $25 at the jy and new u joints was a hell of a lot cheaper than tom woods or having an XJ factory one re-lengthed.

 

X2 on the used one , i found on kijiji 50$ From an owner parting out 3 xj's i gotta go remove it myself a jy local sells them for 115$ I saw some rebuild kits for around 100 us 3 new U-joints and the ball socket joint that is the center of the double cardan already pressed in this kit makes it as easy to rebuilt as a regular U-join drive shaft few extra steps n parts . I plan to rebuild my front and back together .that kit comes with spicer joints. So for being north of the boarder this likely cost me 150 rebuild kit, 50 used drive shaft 200 about total if i want them ballance checked would be extra but I run them first one at a time.

 

Hey Bhicks how did everything go ? I got my RE 3.5" kit finally after a month and worked on it a few weekends I got everything in RE Track bar too. Had to do my rear break lines and both front break lines snapped and pulled them out re-ran them all just waiting on front extension hoses want them as SS flex. All thats left is to bleed and torque my bolts then test drive it. I ordered a Hack and Tap SYE a month ago now from dirtbound and just last week I called and asked them wheres my stuff and they seemed like they dropped my order between the cracks bummer.

I cut some LCA bolts that were stuck good and I recommend a diablo carbide blade for sawzall had to torch the pressed in pins on the sway bar link pin too and pound it while a friend held a pickle fork on the other side of the bracket take the bounce out. If he had not stopped in and had his torches on him I'd be there pounding still.