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General Forums => The Mess Hall => Topic started by: BOOGIE444 on October 24, 2007, 12:49:19 PM

Title: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 12:49:19 PM
I plan on going with a rough country 4" lift, it comes with a transfer case lowering kit do I still need a sye & new longer rear driveshaft to avoid drivetrain vibrations and problems???  Oh and the lift is for a TJ.

Sorry for another newb quesiton......
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 24, 2007, 12:51:59 PM
Not right away but if you want to remove that transfer case spacer you will need one.  Well that really depends on how much offroading you plan on doing.  If it's little to none then you should be ok with just the shims.  Still it's best to do it right and get the SYE.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 01:05:04 PM
I dont mind having the transfer case shims in there, I just dont want the drivetrain to shake itself apart.  So when you install a sye a longer driveshaft is req's right?  You cant just put a sye in by itself?

Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 24, 2007, 01:24:22 PM
I dont mind having the transfer case shims in there, I just dont want the drivetrain to shake itself apart.  So when you install a sye a longer driveshaft is req's right?  You cant just put a sye in by itself?



No, you need a new driveshaft.  The stock one will not long work.  Not only is it not long enough but it you're also moving from a slip-yoke to a standard U-joint. (or double U-joint aka: double cardon/CV)

If you go offroad then you will want to have the SYE.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 01:33:03 PM
Why do you feel a sye and driveshaft is necessary for offroad but no so much for on road?
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: lanulos89 on October 24, 2007, 01:59:49 PM
bc on road you dont flex much and the angle of the shaft dont change much.  off road the angle changes numerous amounts of times.  plus if you blow apart you rear axle, you can simply unbgolt your driveshaft and drive home.  w/o the sye you can't rlly drive w/o pluging the hole in the tcase., or you will loose all your fluid.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 24, 2007, 02:10:09 PM
Why do you feel a sye and driveshaft is necessary for offroad but no so much for on road?

First off you're raising the jeep 4" but you're only lowering the transfer case 1".  This brings the driveshaft out of phase which can cause vibrations.  You can get cam'ed control arms bolts to help move the pinion back into phase though.  The angle is still fairly steep even with shims.  This means the U-joints will be doing more work and wear out faster then normal.  When you're on road, the axle moves very little.  When you're off road it moves a lot more.  Mostly twisting but also some compressing and extensions as well.  With the stock driveshaft you lose that 1" of ground clearance because of the shims.  You also risk having the driveshaft fall out when the suspension is in extension.  Worst case the driveshaft will slide out as you're putting the power on and it cracks the slip yoke or twists the splines.  The slip yokes don't have that much slip built into them.  With the lift, there will be more shaft exposed since there is a greater distance to cover.  When the driveshaft is removed, a 2" hole is exposed and if left unplugged, it will leak badly.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 02:20:03 PM
Thanks guys, I actually understand why a sye is needed, other than just because quadratec says so.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 02:21:21 PM
Looks like I better skip the locker / limited slip idea and put that cash towards a sye & driveshaft.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 24, 2007, 02:39:45 PM
Well if I am going to stick the money in a sye and driveshaft might as well stick a 1" coil spring spacer in there to get 5" of lift, or does this change other stuff too.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: aw12345 on October 24, 2007, 03:10:34 PM
There are several cases to be made for a sye and cv shaft the biggest is when lifting the drive shaft could end up being to short. Now on TJ's removing the rear shaft does not cause an oil leak like a TJ however the stock output shaft is very skinny and can break and will cause an oil leak a SYE addresses this problem with a thicker shaft.
You could lift it 5" if you want with a SYE and cv shaft
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: cmgorman94 on October 24, 2007, 05:07:46 PM
There are several cases to be made for a sye and cv shaft the biggest is when lifting the drive shaft could end up being to short. Now on TJ's removing the rear shaft does not cause an oil leak like a TJ however the stock output shaft is very skinny and can break and will cause an oil leak a SYE addresses this problem with a thicker shaft.
You could lift it 5" if you want with a SYE and cv shaft

What? Does anyone know what that babble means?  What size tires do you want to run with 5" of lift? For 33s you definitely won't need that much, and I wouldn't do it. That's just my opinion though.  The less lift you can run for the tire size the happier and more stable you'll be.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Bounty Hunter on October 24, 2007, 11:30:27 PM
5" is a lot of height for a short-arm type lift, will cause lots of problems offroad and on.  Like mentioned above, use as little lift as possible to clear your desired tire height.  A 3" or 3.5" kit works well with a 1" body lift.

You can get a good SYE for as low as $180, and I recommend getting a used TJ or XJ front driveshaft and having it shortened for use in the rear with the SYE.  Save you a lot of $$.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 25, 2007, 07:04:55 AM
Ok, I will stick with 4" lift, and if it looks to wimpy I will stick a 1" body lift on it at a later time.  Where do they sell sye for $180?  The lowest I seen is on quadratec for $219.00.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Bounty Hunter on October 26, 2007, 02:17:04 AM
http://www.performanceoffroadcenter.com/oscommerce/product_info.php?products_id=153

I've installed about a 1/2 dozen of these kits.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: lax22 on October 26, 2007, 07:36:10 AM
4 inch will not look whimpy. What you also have to remember is that having a 4 banger you also have less weight up front. So when you add a lift that is designed to compensate for the extra weight of a six cylinder, you end up getting a little more lift out of the front end so you can get away with a little bit larger tire. I Bought my jeep with a 4 inch superlift already on it. Yes it dose have the spacers not the SYE, but if i could do it over i would get the 2.5 old man emu with a 1 BL. IMO Just the right ammount of lift so you can easily fit 33's and not look whimpy at all :thumb:
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: black99tj on October 26, 2007, 08:52:15 AM
Get a hack and tap Rubicon Express SYE with a CV RE driveshaft. Way cheaper, and with a 4 cylinder the output shaft doesn't need to be any stronget than it already is with up to 33 in tires.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 26, 2007, 01:01:28 PM
The hack & tap RE sye look alot different than other kinds, it doesnt look like they have a new shaft with them either, do they work??
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: neale_rs on October 26, 2007, 01:06:29 PM
Does anyone have pictures of one installed?  Does it make the output any shorter or does it just eliminate the slip yoke?
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 26, 2007, 01:08:53 PM
Does anyone have pictures of one installed?  Does it make the output any shorter or does it just eliminate the slip yoke?

You replace the output cone so the transfer case is shorter as well as eliminates the slip yoke.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: neale_rs on October 26, 2007, 01:16:04 PM

Thanks.  I found this link too.

http://www.angelfire.com/nc3/84jeepxj/sye.html

I don't know, looks like the spline engagement gets reduced too much.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: BOOGIE444 on October 26, 2007, 02:05:56 PM
I just looked at the hack & tap install linky...

Thats not for me, I will just order a regular sye if I need one.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 26, 2007, 02:10:07 PM

Thanks.  I found this link too.

http://www.angelfire.com/nc3/84jeepxj/sye.html

I don't know, looks like the spline engagement gets reduced too much.

The reason for that length is because that's what the yoke rides on.  You meed a minimum of 2" or so for the yoke.  Since the new yoke won't be moving, it's fine.

Also, if you own a YJ, don't buy a hack & Tap.  YJ's don't have the rear seal in the housing so the Hack & Taps are usually $100 more then the TJ kits.  Strength wise, I've never heard of anyone having trouble with any of the SYE kits.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Bounty Hunter on October 27, 2007, 02:57:24 AM
Also, if you own a YJ, don't buy a hack & Tap.  YJ's don't have the rear seal in the housing so the Hack & Taps are usually $100 more then the TJ kits.  Strength wise, I've never heard of anyone having trouble with any of the SYE kits.
Unless you're like me and have dozens of TJ mainshafts and tailhousings sitting around to use with the H&T.

My H&T works just fine, but it's a little longer than the HD SYE kits.
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Jeffy on October 27, 2007, 01:23:15 PM
Unless you're like me and have dozens of TJ mainshafts and tailhousings sitting around to use with the H&T.

My H&T works just fine, but it's a little longer than the HD SYE kits.

Collecting them I see...  :lol:

The length of the SYE's used to range from 5.5"-4.5".  Then you have the super slim that give you another 2".
Title: Re: Is a sye & drive shaft needed for 4" lift on a TJ ???
Post by: Bounty Hunter on October 27, 2007, 06:53:21 PM
Leftovers from all the SYE installs, spare parts never hurt :whistle: