Need help with JEEP XJ lift
#1
Need help with JEEP XJ lift
so my girlfriend wants her jeep higher than it is now. currently it has 3" coils, 4 leaf packs, and a transfercase drop
i want to add to this, but im unaware of what stuff i do or do not need.
so far the items i think i need are
-1.75" coil spacers
-brake line drop brackets
-adjustable trac bar
-sway bar drop brackets
-2" rear block and u-bolts
-lower front control arms
questions:
-do i need new arms to go 4.5" in the front? (i will probably remove the stock isolator so it is approx 4.25" total)
-do i need upper arms for this amount of lift?
-will i need a SYE? most places saying ill be fine with a tcase drop under 6" lift
thanks!
i want to add to this, but im unaware of what stuff i do or do not need.
so far the items i think i need are
-1.75" coil spacers
-brake line drop brackets
-adjustable trac bar
-sway bar drop brackets
-2" rear block and u-bolts
-lower front control arms
questions:
-do i need new arms to go 4.5" in the front? (i will probably remove the stock isolator so it is approx 4.25" total)
-do i need upper arms for this amount of lift?
-will i need a SYE? most places saying ill be fine with a tcase drop under 6" lift
thanks!
#3
#5
quotes
I have a 4.5 RC lift and i wish i would have gotten the sye at the same time.
I had my RE 4.5 kit on and had a TC drop and some angle shims, it was drivable little vibes nothing big. But I eventually got an SYE and MAN what a difference, I recommend one it drives aloot better.
What is a SYE?
A Slip Yoke Eliminator (SYE) adapts the rear end of the factory transfer-case from a Slip Yoke style to a Fixed Yoke Style.
The origonal design for the XJ Cherokee rear driveshaft is set up with what is called a single cardan rear driveshaft with a fixed length, fixed at the pinion, and slipping at the Transfer Case to make up for droop and compression of the rear suspention.
An SYE eliminates the slip yoke on the t-case tailshaft by changing it to a fixed mounting point for the rear driveshaft, moving the slip yoke to the driveshaft. This also allows some u-joint setups with higher angle capability for a more vibration free ride down the road.
There are two main types of SYE's, based on the output shaft that is used. The "HD" SYE uses a larger 32 spline output shaft, and is made by various top name vendors. The standard SYE kit provides a shortened stock 28 spline output shaft. One company offers a standard SYE kit without providing another output shaft, so the existing shaft is cut, then drilled and tapped for the new flange bolt. This kit is referred to as a "Hack and Tap".
The main issue with the Factory Slip Yoke is the increased angles on the rear driveshaft after lifting a Cherokee. The more lift, the steeper the angle. The increased angles can cause issues with yoke clearance on the factory slip yoke and increased wear on u-joints. A common fix to cure the yoke bind issue is to use a Slip Yoke from a YJ wrangler.
The increased angle also causes a need to Shim the rear axle to re-set driveline geometry and reduce vibrations. The problem with re-setting the geometry is that this causes the angles to be even steeper because in most cases, the pinion needs to move down and be parallel with the t-case out put. This increases the angles on the rear driveshaft more and more, and (the biggest issue) causes the slip yoke to be pulled out of the tail-cone more than is comfortable, and can cause the slip yoke to pull clean off the t-case mainshaft.
The fix for this is to run a Slip yoke eliminator and a rear driveshaft with a slip joint in it.
There are two main driveshaft choices -
another single cardan (one u-joint at each end - two u-joints total) with a slip joint in it
or a "Double Cardan, Near Constant Velocity" drivesahft with 2 u-joints at one end conected by a uni-ball and one u-joint at the other end. These are often refered to (incorectly) as CV driveshafts, and MOST cherokee's have an example of one of these style shafts in the front end for a front driveshaft.
Most cherokee owners opt for the Double Cardan style shaft due to the increased angle it allows, and the corect pinion angle geometry allowing for a higher clearance under the pinon.
Most driveshaft makers (local or mail order) will have some system of measuring on the vehicle to determine the needed length of your new driveshaft once you have your SYE installed. Talking with them will insure you get your order correct.
If you choose to go with a Hack and Tap SYE, you might need to have a flange syle driveshaft, and in talking with your drivesahft maker, you should mention this, and make sure he has all the adaptors and will get you the parts you need.
I encourage you to search here on and make your own decisions as to what SYE to run, proper driveline geometry, whch rear driveshaft will work best for you, and all of that.
When do I need one?
The general rule of thumb on lift height and need for an SYE goes as follows:
1984-1995 = SYE needed at 4.5" ACTUAL LIFT HEIGHT - ok at 3" lift
1996-2001 = SYE most deffinately needed at 4.5" lift, and most need one at anything over the 2" Budget boost.
These are general guidelines, and you will hear people needing SYE's at 2" and you will hear of people running no SYE and 6" of lift - it is all dependant on the vehicle and the ownwers description of "Fine".
If you put on a lift, and then notice driveline vibrations, this is most likely due to the rear driveshaft, and could possibly be that you need a SYE and driveshaft.
While you may be able to live with your driveshaft vibrations and how that affects you, it is certanly not good for the t-case bearings and seals.
If a Lift Kit is sold with a "transfer case drop", a "motor mount lift", or a "high clearance slip yoke" - thoes are bandaids for a real problem - the REAL solution is to use a Slip Yoke Eliminator and a new driveshaft.
I encourage you to do all your own research as to if you need an SYE and the cost effective ways to run them and how they work.
Good Luck!
-XJ_Ranger
A Slip Yoke Eliminator (SYE) adapts the rear end of the factory transfer-case from a Slip Yoke style to a Fixed Yoke Style.
The origonal design for the XJ Cherokee rear driveshaft is set up with what is called a single cardan rear driveshaft with a fixed length, fixed at the pinion, and slipping at the Transfer Case to make up for droop and compression of the rear suspention.
An SYE eliminates the slip yoke on the t-case tailshaft by changing it to a fixed mounting point for the rear driveshaft, moving the slip yoke to the driveshaft. This also allows some u-joint setups with higher angle capability for a more vibration free ride down the road.
There are two main types of SYE's, based on the output shaft that is used. The "HD" SYE uses a larger 32 spline output shaft, and is made by various top name vendors. The standard SYE kit provides a shortened stock 28 spline output shaft. One company offers a standard SYE kit without providing another output shaft, so the existing shaft is cut, then drilled and tapped for the new flange bolt. This kit is referred to as a "Hack and Tap".
The main issue with the Factory Slip Yoke is the increased angles on the rear driveshaft after lifting a Cherokee. The more lift, the steeper the angle. The increased angles can cause issues with yoke clearance on the factory slip yoke and increased wear on u-joints. A common fix to cure the yoke bind issue is to use a Slip Yoke from a YJ wrangler.
The increased angle also causes a need to Shim the rear axle to re-set driveline geometry and reduce vibrations. The problem with re-setting the geometry is that this causes the angles to be even steeper because in most cases, the pinion needs to move down and be parallel with the t-case out put. This increases the angles on the rear driveshaft more and more, and (the biggest issue) causes the slip yoke to be pulled out of the tail-cone more than is comfortable, and can cause the slip yoke to pull clean off the t-case mainshaft.
The fix for this is to run a Slip yoke eliminator and a rear driveshaft with a slip joint in it.
There are two main driveshaft choices -
another single cardan (one u-joint at each end - two u-joints total) with a slip joint in it
or a "Double Cardan, Near Constant Velocity" drivesahft with 2 u-joints at one end conected by a uni-ball and one u-joint at the other end. These are often refered to (incorectly) as CV driveshafts, and MOST cherokee's have an example of one of these style shafts in the front end for a front driveshaft.
Most cherokee owners opt for the Double Cardan style shaft due to the increased angle it allows, and the corect pinion angle geometry allowing for a higher clearance under the pinon.
Most driveshaft makers (local or mail order) will have some system of measuring on the vehicle to determine the needed length of your new driveshaft once you have your SYE installed. Talking with them will insure you get your order correct.
If you choose to go with a Hack and Tap SYE, you might need to have a flange syle driveshaft, and in talking with your drivesahft maker, you should mention this, and make sure he has all the adaptors and will get you the parts you need.
I encourage you to search here on and make your own decisions as to what SYE to run, proper driveline geometry, whch rear driveshaft will work best for you, and all of that.
When do I need one?
The general rule of thumb on lift height and need for an SYE goes as follows:
1984-1995 = SYE needed at 4.5" ACTUAL LIFT HEIGHT - ok at 3" lift
1996-2001 = SYE most deffinately needed at 4.5" lift, and most need one at anything over the 2" Budget boost.
These are general guidelines, and you will hear people needing SYE's at 2" and you will hear of people running no SYE and 6" of lift - it is all dependant on the vehicle and the ownwers description of "Fine".
If you put on a lift, and then notice driveline vibrations, this is most likely due to the rear driveshaft, and could possibly be that you need a SYE and driveshaft.
While you may be able to live with your driveshaft vibrations and how that affects you, it is certanly not good for the t-case bearings and seals.
If a Lift Kit is sold with a "transfer case drop", a "motor mount lift", or a "high clearance slip yoke" - thoes are bandaids for a real problem - the REAL solution is to use a Slip Yoke Eliminator and a new driveshaft.
I encourage you to do all your own research as to if you need an SYE and the cost effective ways to run them and how they work.
Good Luck!
-XJ_Ranger
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Like suggested, if you're going to stick with short arms you need a minimal of lower adjustables at 4.5" of lift. The stock arms, when lifted that high pull your axle back towards the driver and the axle will not be centered in the wheel wells. This also leads to a drastic caster change and will effect on road steering/handling. The track bar is a good idea. Don't get one with a tie rod end design though like the Rusty's; its crap (I know, I currently have it). Upgrade to a double sheer track bar like the one I just bought from Iron Rock Offroad (free shipping right now too). It's worth the money, believe me.
How long till you pull the trigger on this? I should be installing my long arms this week (I have wed, thur, fri, sat off) and won't need my short arms anymore. They are an adjustable Rusty's lower and Iron Man adjustable uppers. Both arms are quality (even though some of Rusty's stuff is junk). I was going to sell them for $150 for all four, would you be interested?
Also, the harsher ride comes from the angle of the arms. The higher you lift it with short arms, the steeper the angle. In stock form the arms are parallel to the ground, so the force of impact on the axle passes through the coils and shocks and not so much through the arms and body. But with higher angles the impact shocks are passing through the arms into the body mount locations simply due to the way the load is transferred with the suspension geometry. This is a lot of the reason why people go long arms. It puts the arms back to close to parallel for better force distribution on the suspension.
Last edited by D94R; 01-05-2010 at 09:16 PM.
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so my girlfriend wants her jeep higher than it is now. currently it has 3" coils, 4 leaf packs, and a transfercase drop
i want to add to this, but im unaware of what stuff i do or do not need.
so far the items i think i need are
-1.75" coil spacers
-brake line drop brackets
-adjustable trac bar
-sway bar drop brackets
-2" rear block and u-bolts
-lower front control arms
questions:
-do i need new arms to go 4.5" in the front? (i will probably remove the stock isolator so it is approx 4.25" total)
-do i need upper arms for this amount of lift?
-will i need a SYE? most places saying ill be fine with a tcase drop under 6" lift
thanks!
i want to add to this, but im unaware of what stuff i do or do not need.
so far the items i think i need are
-1.75" coil spacers
-brake line drop brackets
-adjustable trac bar
-sway bar drop brackets
-2" rear block and u-bolts
-lower front control arms
questions:
-do i need new arms to go 4.5" in the front? (i will probably remove the stock isolator so it is approx 4.25" total)
-do i need upper arms for this amount of lift?
-will i need a SYE? most places saying ill be fine with a tcase drop under 6" lift
thanks!
2in blocks
extended brake lines
Both upper and lower control arms
The rear trac bar
Remove rear sway, Get a JKS disco for the front(only JKS others are junk)
I have a 6.5 without an sye, Youll be fine.
All of those parts can be bought from roughcountry.com
you should be able to run 34's, 35's with trimming
Any other questions feel free to pm