The Official SYE (Slip Yoke Eliminator) Thread

Serbonze said:
Just updating...

The parts list for a SYE install on my 2001 TJ with NP231 transfer case:
Advanced Adapters SYE and Adams Driveshaft. I'm not going with a super short because I have no plans for a tummy tuck. This includes bearing and seals. Ordering from Adams Driveshaft as a kit for $470 shipped.

Transfer case skid plate bolts to replace the longer bolts from the TC drop. Mopar part number 6035836. I ordered these up from Morris 4x4 for $42 shipped (price matched).

Angled rear track bar relocation bracket from Metalcloak for $49 shipped.

Transfer case chain from Borg Warner part number HV-027. I ordered this from eBay for $59 shipped.
Click to expand...


Last question then ready to BUILD! MOPAR Skid plate bolts mentioned state they do not fit a 2004 TJ Sahara. Are any others recommended as I have been searching all over and cannot find these without running into a TC drop package.
 
Jmarce22 said:
Last question then ready to BUILD! MOPAR Skid plate bolts mentioned state they do not fit a 2004 TJ Sahara. Are any others recommended as I have been searching all over and cannot find these without running into a TC drop package.
Click to expand...

Found it. For those that are in need of new TC skid plate bolts for a 2004 - 06 TJ you will need Part no: 6508760AA-M screws and Part no: 6506629AA-M nut from Morris. Strange it did not come up on the Google the first 37 times I tried.
 
JamesAndTheSahara said:
So for my own sanity... I have 3” SL and stock driveshaft with no vibrations. Other than to correct the driveline/pinion angle, why would I want one? Just curious.
Click to expand...
If you have no issues with vibrations, I don't know why you would want an SYE. Maybe a longer drive shaft if yours is almost fully extended, but you could have a drive shaft shop modify yours to add length. Unless you just want a new one, of course. :D
 
SO, when installing an SYE, (97 jeep tj) would you most always install a new chain, even if your not having a chain problem?

I have a 4" lift and the t-case shift linkage has a drop bracket on it, so after the install and the belly pan is back to its original position Im guessing i would just remove the drop bracket and restore the linkage to its original position??
 
Serbonze said:
I replaced mine. The case was open anyway and it was only an extra $60.
Click to expand...
i looked at the t case closely and it looks kinda like someone has been in it before because there's a good bit of sealant around the case, unless it comes from the factory that way. there is no record of work done on the t case in the records.
 
Recently acquired a LJ with a 4" Fabtech lift. This kit includes what appears to be approximately 2" spaces for the transfer case drop. Based on this thread, due to the longer wheel base, there's no need for these spacers? Thread starter indicated LJ owners don't need SYE and drive shaft due to the longer wheel base.

Should I elect to do a SYE and axle and remove these transfer case spacers, would I technically still need to angle the pinion, or could I just leave it alone in the stock config?

Thanks!
 
wilson234 said:
Recently acquired a LJ with a 4" Fabtech lift. This kit includes what appears to be approximately 2" spaces for the transfer case drop. Based on this thread, due to the longer wheel base, there's no need for these spacers? Thread starter indicated LJ owners don't need SYE and drive shaft due to the longer wheel base.

Should I elect to do a SYE and axle and remove these transfer case spacers, would I technically still need to angle the pinion, or could I just leave it alone in the stock config?

Thanks!
Click to expand...

If you have an LJ, you should be able to take those spacers out, as the longer wheel base should allow you to get by without them. Take them out first, see if you get vibrations, and if you do you can either put them back or get a SYE (the latter being the more appropriate way to do it).
 
  • Like
Reactions: ac_
Chris said:
This thread is designed for the sole purpose of informing members as to why it is important to put a SYE on your lifted Jeep Wrangler. Now we can answer the “Do I need a SYE” questions by simply pointing people to this thread. I hope this thread will help new members make the right choice when installing a lift on there TJ.


What are Slip Yoke Eliminators and why should they be used?

What is a SYE and why is it used?
SYE stands for Slip Yoke Eliminator. The Slip yoke is the yoke that slides over the output shaft of the transfer case. This is the yoke that the rear driveshaft connects to at the Transfer case.

The SYE kit replaces the stock slip yoke and housing with a sealed housing and a fixed flange or yoke. This fixed flange or yoke is what a new CV style driveshaft will bolt up to. A CV (constant Velocity) shaft uses two U joints instead of a single one and this allows for much steeper angles. These shafts also utilize a two piece design that allows for suspension travel by allowing the shaft itself to compress and extend verses the yoke sliding on the output shaft. The sealed output now also allows for the rear driveshaft to be removed from the vehicle and not allow the transfer case fluid to empty out of the transfer case.


When should a SYE be used?
The stock rear driveshaft is a fixed length unit that relies on the slip yoke to adjust when the suspension travel. When lifting an TJ, the angle between the rear axle pinion and the slip yoke become much greater. The factory setup was not intended for these variations in lift. The angle difference will be most noticeable in the fact the slip yoke will be pulled further out of the housing than before the lift.

The differences in angle can be attributed to several things, but they all revolve around this center point, the length of the rear driveshaft. You will hear various things from various people about what size lift can be ran without a SYE. The key here is to recognize the differences between their TJ and yours.


What are some of the harmful effects of not using a SYE?
The difference in the angles put a strain on the output shaft. This places load on the transfer case bearings and the seals on the output shaft.

Another, more obvious problem, are the U joint ears of the driveshaft making contact with the slip yoke as the driveshaft spins. This will make for a noticeable clanking noise and hard vibration. A transfer case drop will clear that problem up, as well as a high clearance extended slip yoke, but it will not correct the strain on the output shaft.


What are other positives does the use of a SYE provide?
As mentioned before the ability to remove the rear driveshaft if damaged and drive off a trail under the power of the front axle is a major plus. If you run a stock front driveshaft with a SYE, you can carry a spare for both the front and the rear driveshafts.


Hack N/ Tap vs. SYE
There are two different styles of SYE’s out there. There is the HD Slip Yoke Eliminator, and then there is the Hack N’ Tap. The two are relatively different but the end result is going to be relatively the same. With the HD SYE the output shaft inside the transfer case is actually going to be replaced making the SYE the stronger of the two options. With the Hack N’ Tap you actually cut the OEM output shaft then add a flange on it which will then connect to the new CV driveshaft.

In summary, a true SYE is going to be a better option versus the Hack N' Tap. However, if you are on a budget a Hack N' Tap will certainly get the job done.


Rear Shocks
After adding a SYE you may encounter some rear shock issues (especially if you're lifting it over 2 inches). When you rotate the pinion up to match the transfer case output yoke, the lower portion of the shock body may rub on the lower spring perch.

The cheap and easy way to fix it are these Currie CE-9601 Rear Lower Shock Mount Extensions.

The proper way (in my opinion) to fix it, is to relocate your spring perches using something like this. This will of course require a competent welder, but it's really not that hard of a job.


Which SYE do you recommend?
If you're fortunate enough to have the NP241OR Rock-Trac transfer case (only found in the 03-06 TJ and LJ Rubicon models) then you don't need a SYE, since this transfer case already has one from the factory.

If you're like the majority of us however and have the NP231 transfer case as found in all the other TJ and LJ Wrangler models, there are various options in regards to SYE kits, but one of the most popular and well regarded is the Advanced Adapters SYE.

There's certainly a lot of other options out there which I won't even begin to list, but the Advanced Adapters SYE is my favorite.


What if I have an LJ?
Lucky you! The LJ in most cases is fun up to about 4-4.5" of lift without a SYE or double cardan (CV) driveshaft! That's one of the benefits you get from the LJ with it's longer wheel base... much less extreme driveline angles.
Click to expand...
Chris, how can I check to see if my 2005 Rubicon has the NP241OR Rock-Trac transfer case?
 
Serbonze said:
Hey Chris...I'm about ready to pull the trigger on a SYE kit, and during my research I found a few things that are not discussed very often. The prior owner of my Jeep installed a 4" lift kit that included a rear track bar relocation bracket and a transfer case drop.

Since the rear pinion will need to be adjusted up to match the angle of the output shaft from the transfer case, the rear track bar can bind in the standard bracket. Because of the possibility of binding, I purchased an angled relocation bracket. You can find them for around $60. I picked up mine from Metalcloak, since the rest of the suspension is from them and I like their products.

The transfer case drop uses much longer bolts because of the spacers, so you will need the standard Mopar bolts or equivalent. Mopar part number 6035836.

While the transfer case is open it's a great time for some preventative maitenance. A new chain is anywhere from $70-$140 depending on the manufacturer. I've found options from Alloy USA, Mopar, Borg Warner, and Crown. Another maitenance item is to pick up a seal kit that runs about $40.
Click to expand...

Based on this thread and particularly your notes, I purchased the Adams Drive Shaft with Teraflex Mega Short SYE. It was a great deal and in the ballpark for what I wanted to spend. I was also researching the angled bracket for the rear track bar and came across a thread recommending an adjustable track bar for use in these brackets. They mentioned that due to the change in angle, if you have a solid rear track bar, you will not be able to "twist" it as the angle changes. I found a kit on ExtremeTerrain that has both for $251 (JKS brand). All that being said, I will NEED to adjust my pinion angle. I have both fixed upper and lower control arms right now. I saw a YouTube video saying you only needed adjustable upper OR lower to adjust the pinion angle. It recommended upper (increase length of upper to kick the suspension back and raise the front of the diff). On a budget, do you think this would work? With the adjustable track bar and the relocation bracket, my budget is pretty tight already. Just getting the upper adjustable control arms to achieve the desired pinion angle for the CV would help my pocketbook for sure. Since I know you will ask.... 2006 Wrangler SE (Dana 35 Diff) with 3.5" lift. I have a 1.5" TC drop right now that I will take out when I get the SYE and CV installed. Even with the 1.5" TC drop, I still get a driveline vibe at 45 mph that goes away past 50 mph and returns (heavier) at 60-75 mph....haven't ventured above that.
 
In my opinion, you can get by with just the Upper Double adjustable control arms. Its makes it SOOOOO easy to adjust your pinion angle. Stay in contact with Dan at Adams and he will get you where you need to be as far as pinion angle . The pinion nut has to point at the out put shaft yoke nut.
The reason for the adjustable track bar and bracket is when you adjust your pinion angle up of course it rotates your axle... and your OEM track bar will mash into your gas tank skid plate. So with the adjustable track bar and angled bracket it gives the track bar room to move without contacting anything.

Later when you buy the lower adjustable control arms it will give you the ability to fine tune your wheel base if needed. ya know its always a give and take thing.
Hope I didnt leave anything out. There lots of folks here that can even tell you more.
 
  • Like
Reactions: McMac1447 and Thunderhead
Hi, I just had a rough country 4 inch long arm suspensions lift kit and a rough country 2 inch body lift this past week and i’m looking into getting a rear CV driveshaft and a SYE for my jeep. It’s a 2001 4.0L 6 cylinder Wrangler TJ Sport and the main reason i’m thinking about getting one is to fix my shifting. It has a 5 speed and ever since it’s been lifted i’m unable to get the jeep into 2nd gear and i was wondering if this would be the proper way to fix such an issue? thanks
 
cameronblizz said:
Hi, I just had a rough country 4 inch long arm suspensions lift kit and a rough country 2 inch body lift this past week and i’m looking into getting a rear CV driveshaft and a SYE for my jeep. It’s a 2001 4.0L 6 cylinder Wrangler TJ Sport and the main reason i’m thinking about getting one is to fix my shifting. It has a 5 speed and ever since it’s been lifted i’m unable to get the jeep into 2nd gear and i was wondering if this would be the proper way to fix such an issue? thanks
Click to expand...
also im not sure if i’ve had my transfer case lowered i haven’t looked (i’m new to mechanics as i’m only 17 so i’m slightly unfamiliar with some things) thanks again
 
cameronblizz said:
also im not sure if i’ve had my transfer case lowered i haven’t looked (i’m new to mechanics as i’m only 17 so i’m slightly unfamiliar with some things) thanks again
Click to expand...
Look for the TC drop, I would be surprised if you had 4” lift with no TC drop and not felt some significant vibes along the driveline. The TC drop is simply spacers between the skid plate on the bottom and the frame. They just look like big black pucks. It is a cheap fix to driveline vibrations to fix pinion angles. Not sure an SYE will fix your shifting problems. Someone else may know on this thread (one of the best I have seen by the way) Is it an automatic? If so, you may want to look at your shift linkage for your transmission AND your transfer case. Both run down the driver side of the transmission and after lifts, they may be in slightly different positions. In an automatic, some time the shifter for the auto transmission will run into the linkage for the transfer case (4WD). This could explain your problem. To check, get a friend, chalk the wheels, set the brake, turn on your vehicle, and have your friend cycle through the transmission gears or try to put it in 2nd. If you lay next the vehicle (not all the way under it, you will see the linkage moving and might be able to see where it is binding. If it is an auto, this could be the problem. I ran into a lot of forums that discussed this problem early on in my exploration. If it is a manual, someone else will have to chime in.
 
Top Bottom
Back