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Topic Review (Newest First)
05-12-2013 08:22 PM
GoldenSahara00
Quote:
Originally Posted by Jeeping it real View Post

Come on?! Your ability to regurgitate the redundant information given multiple times over in this forum doesn't quite classify your answer as "high quality".

To the OP, I wasn't trying to be rude in any way. This forum and community have answered many of my first time jeep questions over and again. Perhaps I'm among few who do extensive research, draw my own conclusions, and ask questions afterwards... I don't know. My point is the search bar is there, and it works wonderfully. Ask a guy like me, I use it repeatedly. All I'm am saying is that the info you have acquired with this post, is the same as you would find by tapping on the keyboard under the search board. Best of luck to you, and happy Jeeping. Stay thirsty my friends.
At least my response actually qualifies as an answer. I didn't regurgitate anything, simply defined an object and explained its basic use. I promise no one on these boards was the first person to use a SYE. Your ability to tell the OP to search classifies you as one of the new, arrogant annoying posters who have driven off countless members of this forum because you don't have the good manners and decency to simply answer a question. Yes he could have searched. It's not that hard to use the Internet. I usually assume someone is asking a question because they tried to find it and couldn't. Believe it or not, there was a time when it was okay to ask questions without someone responding with "just search for it".

OP and others interested, here is a great link to some more info, specifically on driveshaft geometry. Click the links to some of the other parts as well and read around. http://www.pirate4x4.com/tech/billav...ft/index2.html
05-11-2013 09:41 AM
woggie
Quote:
Originally Posted by SCORE5150 View Post
Jerry, you always amaze me with your no nonsense straight forward answers, along with your cool diagrams!
Thanks Jerry, another great answer! As always thanks for taking the time and effort to help pass along useful information.
05-11-2013 12:53 AM
SCORE5150 Jerry, you always amaze me with your no nonsense straight forward answers, along with your cool diagrams!
05-10-2013 10:31 PM
Jeeping it real P.S. I used to live in South Carolina, Shaw AFB to be exact. Used to roll to Myrtle Beach almost every weekend. That state is by far one of the better places I've been.
05-10-2013 10:26 PM
Jeeping it real
Quote:
Originally Posted by GoldenSahara00 View Post
It was worse than low quality, it was worthless. I'm pretty sure he didn't need you to tell him how to use the search function or google. I mean he found this site before you after all.

khall7, the SYE benefits you by allowing you to run a different type of driveshaft geometry which is more suited for extreme driveshaft angles, that you would see on larger lifts like 3"+. You however need to be able to set the rear pinion angle to use it, meaning you need one or both sets of aftermarket adjustable control arms.
Come on?! Your ability to regurgitate the redundant information given multiple times over in this forum doesn't quite classify your answer as "high quality".

To the OP, I wasn't trying to be rude in any way. This forum and community have answered many of my first time jeep questions over and again. Perhaps I'm among few who do extensive research, draw my own conclusions, and ask questions afterwards... I don't know. My point is the search bar is there, and it works wonderfully. Ask a guy like me, I use it repeatedly. All I'm am saying is that the info you have acquired with this post, is the same as you would find by tapping on the keyboard under the search board. Best of luck to you, and happy Jeeping. Stay thirsty my friends.
05-10-2013 07:46 PM
Jerry Bransford The short answer is a SYE shortens the transfer case's output shaft so a longer rear driveshaft can be installed. Why? To reduce the angles the driveshafts have to work into to eliminate drivetrain vibrations. And stay with me until near the bottom where things get italicized again... that part should put much of this together.

Why in the world is a longer rear driveshaft desirable? Because the TJ's wheelbase is so short, the rear driveshaft has to be short. That the rear driveshaft is so short means its angle is affected greatly by suspension lifts. The taller the suspension lift, the significantly steeper a short driveshaft becomes. Being able to install a longer rear driveshaft means its angle is less affected by suspension lift height.

Because a longer aftermarket rear driveshaft's angle is less steep with any given suspension lift height, that means the u-joints at both ends of the driveshaft can work into reduced angles and are thus less likely to vibrate which is the root cause of drivetrain vibrations.

So the bottom line is that tall suspension lifts causes drivetrain vibrations because they steepen the driveshaft angle excessively which creates excessive angles for the u-joints to have to work in which, again, is the root cause of drivetrain vibrations. A SYE kit reduces that driveshaft angle down enough that an aftermarket driveshaft can work without vibrating.

The first drawing below shows the stock drivetrain & factory driveshaft which has two u-joints. You can see that increasing the height difference between the t-case & rear axle would steepen the u-joint angles.



The next drawing below shows after a SYE is installed. Its driveshaft has three u-joints.



The second above drawing doesn't reflect the shorter t-case output shaft but it shows the type of aftermarket driveshaft that gets installed which is called a CV (constant velocity) driveshaft, aka known as a double-cardin driveshaft.

The 3 u-joints in the CV driveshaft do some neat magic. When a CV driveshaft is installed with a SYE kit, the rear pinion angle gets raised to match the driveshaft angle. You can see that in the second drawing above. Next, look at that rear-most u-joint. It is working into zero (0) degrees. Same angle going into it as is going out.

Then look at the two front u-joints inside the CV joint. The remaining angle between the driveshaft and transfer case output shaft is neatly divided by those two u-joints. That means those two u-joints are working into only half the angle that a single u-joint would have to. So the rear u-joint has zero angle to contend with, and each of the front two u-joints only have a very mild angle they have to contend with. Voila, a very cool way to reduce the angles the driveshafts have to work into which means no drivetrain vibrations.


I hope that brief explanation of why a SYE kit and CV driveshaft is so cool to install for taller suspension lifts made sense.

Above drawings courtesy of Tom Wood's very cool SYE & driveshaft site at http://www.4xshaft.com/
05-10-2013 07:42 PM
GoldenSahara00 Good link^
05-10-2013 07:38 PM
Tjkidd
Quote:
Originally Posted by GoldenSahara00 View Post
It was worse than low quality, it was worthless. I'm pretty sure he didn't need you to tell him how to use the search function or google. I mean he found this site before you after all
You sir are amazing, "use the search bar" seems to be the only real answer anymore.
05-10-2013 07:22 PM
UnlimitedLJ04 Better tech info here:

What is a CV shaft and why do I want one? - JeepForum.com
05-10-2013 07:12 PM
gbendezu
Quote:
Originally Posted by pineda22 View Post
beat me to it gbendezu!!
Sorry man, didn't mean to steal your thunder haha
05-10-2013 07:10 PM
O_M_Jeep This is one of those topics that gets to clogging up a forum, when people ask instead of reading whats out there already, I got 1.28 million hits on Jeep SYE, none of them from this site so you can add about 75 threads to that, I got over 4k image results and over 1000 youtube video results. I didnt find the answer as useless as the new thread to ask a question thats been answered 1.28 million times already.
05-10-2013 07:02 PM
Water Dog Khall7, moving the slip part of the shaft to the center of the shaft rather than on the end of the t case effectively lengthens your drive shaft meaning that there is less of an angle on the driveshaft. On a stock height jeep having the shorter shaft really isn't an issue, but as you raise the Jeep with a lift, the driveshaft angle becomes too much putting stress and clearance issues on the u-joints and related hardware.
05-10-2013 06:58 PM
GoldenSahara00 It was worse than low quality, it was worthless. I'm pretty sure he didn't need you to tell him how to use the search function or google. I mean he found this site before you after all.

khall7, the SYE benefits you by allowing you to run a different type of driveshaft geometry which is more suited for extreme driveshaft angles, that you would see on larger lifts like 3"+. You however need to be able to set the rear pinion angle to use it, meaning you need one or both sets of aftermarket adjustable control arms.
05-10-2013 06:57 PM
pineda22 beat me to it gbendezu!!
05-10-2013 06:57 PM
gbendezu
Quote:
Originally Posted by khall7 View Post
thank you for the legit answer goldensahara. How does that benefit my jeep?
Well when your jeep goes up or down do to offroading or the driveshaft tends to "stretch" since this isn't possible due to it being made of metal the slip yoke allows a section of your driveshaft to slide or SLIP. when you lift your jeep and don't do a tcase drop your driveshaft will pull out some (and be at an awkward angle causing dlvibes) if you do too high of a lift the SY can actually slip off causing your tires to stay stationary since the drive line is no longer connected to the tcase. As mentioned before a tcase drop kit will usually do the trick, however a sye although more expensive is the better route to go about this. Hope that helped you out
05-10-2013 06:43 PM
khall7 thank you for the legit answer goldensahara. How does that benefit my jeep?
05-10-2013 06:41 PM
Jeeping it real I don't think suggesting google or the forum search bar would be considered a "low quality" answer. An answer "lacking detail", possibly. Kudos to you though, haha.
05-10-2013 06:32 PM
GoldenSahara00 Real high quality answer up there. I think you spent more time typing that worthless response than it actually takes to answer.

khall7:

A SYE replaces the slip yoke on the t case, which allows the drive shaft to slide back and forth, with a fixed yoke that a U joint would bolt into. The SYE is coupled with a new style shaft, often called a CV shaft, which is technically a DC or double cardan shaft, which has a slip point built into the shaft itself.

You can tell if you are equipped with a SYE by looking at your t case. If there is a long splined piece that the driveshaft can slip over, you're tcase is stock. If the driveshaft is bolted into a fixed yoke, it has an SYE or is a rubicon transfercase, the np241, or some other tcase.
05-10-2013 06:25 PM
Jeeping it real I'd suggest either google searching "SYE JEEP" or using the search bar on this forum. There is more than enough info on it with in depth details on this forum regarding it. After reading what you come across and you still have questions, come back here and ask. It's pretty simple, good luck!
05-10-2013 06:02 PM
khall7
Sye explanation

I was wondering if y'all could explain to me what a sye is exactly? How can I tell if one has already been put in my rig, and what are the benefits of having one? I'm always looking for ways to upgrade my rig

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