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Front Drive Shaft as Rear + SYE (Minimum Lift?)

M

Markos

NAXJA Forum User
Location
Seattle, WA
Hello:

I've been meaning to install a SYE and use a front drive shaft. I finally picked up the driveshaft from a '98 auto with a 241 t-case.

Will a front driveshaft work with a 2" lift. I don't want to cause any issues at full compression. If not, would the additional 3" gained from a short SYE (like Tera or Rugged Ridge) fix the issue?

If I decide I want a short SYE anyway, will a 2" lift plus the 3" shorter t-case be too much for the factory auto front DS?



P.S. I searched around. I saw some posts on 3" lift, but not much on 2". I suspect that this is because most people skip the SYE when lifting 2"
 
Most people don't skip the SYE at 2-3", they just don't need it till 4" or more, IMO. here's my answer though, maybe, maybe, maybe, were are you going to get a shorter Tcase. Your going to need to measure to determine driveshaft length. personaly i'd do a TC drop first if I got vibes after lift, $5 max. If that didn't solve the problem then SYE. By the way my 96 will run 5.5" with 1" TC drop and has no Vibes.
 
93gc40 said:
Most people don't skip the SYE at 2-3", they just don't need it till 4" or more, IMO. here's my answer though, maybe, maybe, maybe, were are you going to get a shorter Tcase. Your going to need to measure to determine driveshaft length. personaly i'd do a TC drop first if I got vibes after lift, $5 max. If that didn't solve the problem then SYE. By the way my 96 will run 5.5" with 1" TC drop and has no Vibes.
Click to expand...

Sorry, my first post was unclear. By shorter t-case, I meant shorter SYE. Both shorty SYE's that I listed are around 3" shorter than a standard SYE like Advanced Adaptors or the PORC clone.

I want to avoid a t-case drop. I'm only lifted 2", I need all the clearance I can get!
 
My '98 runs 4.5" up front and like 5-5.5" in the rear, with a 242 tcase and 4 degree shims, hardly any vibes. I haven't dropped the t-case either.
However, while we are on the subject, is a front driveshaft as strong as the rear? I've been debating doing this to my Jeep.
 
Just to keep the subject on track. Here are the facts.

  • I have a 2" lift
  • I have vibes
  • I will not drop the t-case
  • I have a spare front driveshaft from a '98 auto
  • I will purchase a SYE full-size or short (not a hack 'n tap)

Will the driveshaft be too long at full compression?
 
I'm wondering why you have vibes at just 2" of lift. I don't think that should happen. If anything try shimming your axle with a minor shim, say 2 degrees.
As far as it being too long, I'm not sure in that. I'd measure your stock rear driveshaft as it is right now and compare it to your front driveshaft, how much the SYE will add to the driveline, etc.
 
codyyy said:
I'm wondering why you have vibes at just 2" of lift. I don't think that should happen. If anything try shimming your axle with a minor shim, say 2 degrees.
As far as it being too long, I'm not sure in that. I'd measure your stock rear driveshaft as it is right now and compare it to your front driveshaft, how much the SYE will add to the driveline, etc.
Click to expand...

My vibes aren't all that bad, but they are noticeable at highway speeds. I haven't shimmed the rear axle yet. I need to swap my leaf springs left-to-right and change the bushings. I'll try the shims then. I'd still like to install the SYE.
 
I'm running a PORC SYE on my DD (1990) with only 2.5" lift. I had vibs that wouldn't go away and I had a spare SYE laying around so it went in. I ran a stock front drive shaft for a year before putting in a spare TW shaft (same length) that I had laying around. No issues at all with either shaft.
 
xjtrailrider said:
I'm running a PORC SYE on my DD (1990) with only 2.5" lift. I had vibs that wouldn't go away and I had a spare SYE laying around so it went in. I ran a stock front drive shaft for a year before putting in a spare TW shaft (same length) that I had laying around. No issues at all with either shaft.
Click to expand...

Was your rear axle shimmed?
 
I sit at 5"s of Lift. No SYE, no Vibes. I have no problems at all.

Could your Rear Driveshaft be Bent or maybe Out of Balance? You could have it Checked and Balanced for just a few Bucks at a Driveshaft Shop.
Because my Front Driveshaft was too Compressed at full drop with the kind of Lift I have, I had it Shortened 1.75"s and Balanced for just $50. Now I have 1/2" of Play in it at Full Drop.
 
Last edited:
cher96 said:
I sit at 5"s of Lift. No SYE, no Vibes. I have no problems at all.

Could your Rear Driveshaft be Bent or maybe Out of Balance? You could have it Checked and Balanced for just a few Bucks at a Driveshaft Shop.
Because my Front Driveshaft was too Compressed at full drop with the kind of Lift I have, I had it Shortened 1.75"s and Balanced for just $50. Now I have 1/2" of Play in it at Full Drop.
Click to expand...

Thanks for the suggestion. I actually called the driveshaft shop today and they quoted me $60 to balance a driveshaft. I thought about having the front balanced since it's used and I don't know the history. Considering that I only paid $20 for the shaft, I figured I'd wait and see how things turn out. If the replacement shaft is out-of-balance I'll swap in my front shaft and search for a new front. That's one of the other reasons why I want to run identical driveshafts.

Once again, my main concern is finding out whether or not a factory front shaft will fit at 2". It's kind of hard to measure because I don't know where the yoke be on the t-case side.
 
Unfortunitly, it is best to measure for a Driveshaft after you do your Modifications to your TC and while it is loaded in weight for whatever you would carry (passengers too). You would measure from Fixed Yoke to Fixed Yoke.

MeasDC_575x240.jpg
 
Front Driveshafts come in different Lengths for an XJ

XJ 87/88 2.5 Automatic 27.950 53003912
XJ 89/93 2.5 Automatic 27.970 53005540
XJ 89/01 2.5 Manual 25.310 53005541
XJ 89/01 4.0 Automatic 30.660 53005542
XJ 89/01 4.0 Manual 29.250 53005543
 
Markos said:
My vibes aren't all that bad, but they are noticeable at highway speeds. I haven't shimmed the rear axle yet. I need to swap my leaf springs left-to-right and change the bushings. I'll try the shims then. I'd still like to install the SYE.
Click to expand...


I just recently had this problem in my 98 with a 6.5" lift. Turns out I had a bent yoke on the output on the tcase for the front drive shaft. The vibes would only appear when doing 65 mph, now they're almost gone (glyde coat on the slip yoke of the shaft is worn out)
 
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