Topic: Time for an SYE

[N8whitie]

Hope everyones weekend went well. Now since I have my 4" BDS lift waiting at home I am almost positive that I am going to need an SYE kit. I've seen a Rugged Ridge kit for about 160 compared to the other brands.. ie... Advanced Adapters, Skyjacker, etc which go for 260+. I've read several reviews on these and haven't heard any complaints on the RR so now I ask you guys. In your experiences with any of the said SYE kits which is the most favorable? Also, it looks like I am going to have to run a CV drive shaft as well. Is that just the front or the rear as well? Is there something online that can tell me the size(s) or am I going to have to wait until I get home to measure myself?

 I know I ask alot of questions and don't have much advice to contribute so I thank you for it. If anyone ever needs to know anything about ships, boats, rigging, crew served weapons or weird skimming equipment I'm on it! haha.

 Thanks again   -N8

[sharpxmen]

you don't need a cv d/s in the front just in the rear. I don't have any experience with the SYEs so i'm no help there, i went with a Dana 300 t-case and ordered a custom cv d/s to length.

[Bounty Hunter]

Not sure if you have a YJ or a TJ, if you have a TJ you already have a CV front driveshaft, and a YJ has a standard driveshaft.  You don't need to do anything to the front driveshaft for a 4" lift.

You will need a CV driveshaft for the rear, I usually pick up a TJ or XJ used front driveshaft and have it shortened & balanced to use in the rear.  I get them shortened/balanced locally for $65 and a used shaft runs about $50, so it's an affordable option.

Rugged Ridge SYE's are every bit as good as other name-brand SYE's.  I usually install a PORC SYE but they're all too similar to worry about.

Don't forget you will need to rotate the rear axle pinion upward after installing the SYE so the pinion is directly inline with the driveshaft.  This requires adjustable upper control arms on a TJ or rewelding the spring perches on a YJ.

[N8whitie]

Thanks, I probably should have mentioned that I have a YJ. So basically the pinion on my rear axle is lower than the output shaft on my transfer case so I have to flip it?? is that right?

[Bounty Hunter]

This is your current setup:


This is what you want when using a SYE and a CV driveshaft:

[Eucalypta]

.....or rewelding the spring perches on a YJ.

Is installing 4 degree shims not enough? Would bigger shims do or is welding really nescessary?

[N8whitie]

Ahhhhh, now I see. Thanks for the diagrams man. But as Eucalypta said I thought thats what the shims where for.

[FourbangerYJ]

Ahhhhh, now I see. Thanks for the diagrams man. But as Eucalypta said I thought thats what the shims where for.

Shims are more of a band-aid. They work but can cause problems if they get spit out. I have seen some that have cracked. Then they got spit out and then the U bolts are loose which causes the housing to turn...
I stay away from shims. I would either cut and reweld the perches or run it without and check/replace the U joint on the axle end of the driveshaft often.

[neale_rs]

If you use shims, make sure you get the ones that are bolted in as part of the spring pack, held in place by the center bolt, not the ones that rely on having a long bolt head that just sticks through the shim.  Also, make sure you use steel shims.  But the best way is not to use them.

[kunasbob]

lots of great info here. I'll be bookmarking this page.
 

[Jeffy]

Shims are more of a band-aid. They work but can cause problems if they get spit out. I have seen some that have cracked. Then they got spit out and then the U bolts are loose which causes the housing to turn...
I stay away from shims. I would either cut and reweld the perches or run it without and check/replace the U joint on the axle end of the driveshaft often.

For just a few degrees I think they're OK.  I recommend steel shims and not the aluminum ones as those can crack and fall out if you're not careful.  Although even those can last as long as your U-bolts stay tight.

The one thing the diagram is missing that that the axle will rotate while under power.  So usually you'll add 2-3* to the pinion to compensate.  Otherwise, the pinion will be 2-3* high.

Oh and if you can geat away without a CV joint then that's a better way to go.  Problem is the rear driveshaft is short.

[FourbangerYJ]

For just a few degrees I think they're OK.  I recommend steel shims and not the aluminum ones as those can crack and fall out if you're not careful.  Although even those can last as long as your U-bolts stay tight.

The one thing the diagram is missing that that the axle will rotate while under power.  So usually you'll add 2-3* to the pinion to compensate.  Otherwise, the pinion will be 2-3* high.

Oh and if you can geat away without a CV joint then that's a better way to go.  Problem is the rear driveshaft is short.

Good point on the power going thru the drivetrain will change the pinion angle.
 
N8 if your kit comes with a T-case drop down use it. That helps get the geometry close enough so you don't need to worry about it.

[sharpxmen]

[...]

Oh and if you can geat away without a CV joint then that's a better way to go.  Problem is the rear driveshaft is short.

why better without the CV joint? I thought is the other way around (my understanding was that transfer angles would be smaller using the double cardan so the stress in the u-joints is reduced) - trying to understand the reason, i'm not saying one way or the other.

[Jeffy]

why better without the CV joint? I thought is the other way around (my understanding was that transfer angles would be smaller using the double cardan so the stress in the u-joints is reduced) - trying to understand the reason, i'm not saying one way or the other.

The CV joint main advantage is extreme angles.  For strength a single U-joint is stronger as long as the angles aren't extreme.

[jfrabat]

For just a few degrees I think they're OK.  I recommend steel shims and not the aluminum ones as those can crack and fall out if you're not careful.  Although even those can last as long as your U-bolts stay tight.

My U-bolts were tightly on, and they were showing cracks when I took them out (just in time, i guess).