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SYE question

T

tech kid

NAXJA Forum User
Location
Lubbock, Texas
i searched and couldnt get a definite answer. lookin at buying a 87 4 door cherokee, 30/35 with 3.55s. its gonna be a budget beater buildup, with a LOW stance to be good and stable. gotta be ready for a trip to moab in august.

heres where my question comes in. gonna use 4.5 coils in the front from RE, and make my own long arms. gettin 4 or 5 inches of lift in the back too, how is undecided at this time. my question comes with will i need an SYE for sure? its gonna be a trail only rig thatll be trailered to the trails. cant quite tell from the stuff ive seen if ill need one or not, mixed answers all over the place.

btw, itll be runnin 35s or 36s, and for those who dont think its possible, i believe in bumpstops and trimming. i hate rigs that sit WAY to high for their tire size, the COG is then too high and its just unneeded. i believe in the low concept with big tires, therefore sawzall and bumpstops are my friend.

thanks for any help

wes
 
You will probably need the SYE, but all XJs are different, so I don't think you can get a definitive answer (for a 4.5" lift) without just trying it. Go ahead and lift your XJ without one, but be sure to leave space in your budget for an SYE in case you need one.

And you can definitely run 35s on 4.5" of lift. If you can weld, you can even retub the rear wheel wells (on a 2 door at least) and run 35s on less lift. Search for pictures of afd516 's XJ. Last I knew he was running 36s on about 3-4 inches of lift, with retubbed rear fenders.
 
if this is trail rig only, then deffinately go with it,
xj rear shafts have a "slip yoke" from the output shaft of the transfercase. this means that at times of articulation and increased/decreased load on the rear. the yoke goes in and out of the transfer case, to make up for the difference. a slip yoke eliminator gets rid of this occurence and basically eliminates the chance for the yoke to slip out of the transfer case, which would leave u leaking and moping.

porc sells a decent one for around 190 which is pretty dang good.

youll need a cv drive shaft, or a stock front driveshaft from an auto so you have a spicer (when the driveshaft is the component with the inward outward motion)

i dont no if you knew all that, just bored thats all

get the sye and save yourself trouble down the road. especially if u decide to go bigger, which u probably will after moab lol
 
The issue with that much lift on a trailer queen is not vibes but the damn rear axle falling out. The slip yoke isn't that long. ANY serious articulation and it'll drop out. Plan and budget for a SYE. Besides, hitting rocks you'll need the extra strength of the shorter/more splined shaft.
 
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so another question along the same lines, if im runnin a slip shaft would i still have the problem of the slip yoke "falling out"???? probly gonna run sqaure shafts front and rear.....oh, and its now gettin an 8.8 out back, cause i got one cheap
 
tech kid said:
... lookin at buying a 87 4 door cherokee ...
... gettin 4 or 5 inches of lift in the back ... will i need an SYE for sure? ... its gonna be a trail only rig thatll be trailered to the trails.
Click to expand...

I ran my 87 4 door (auto) at 4.5" with no SYE and no problems. Ran at 5.5 with no SYE and no problems, except a slight vibe at 65ish that went away at 70. Ran at 6.5" and no SYE for a brief period with shudders at 30, 60, and vibes over 70. I installed a WK slip yoke that fixed those vibes, athough i still got the shudder.

That was with a 29 spline 8.25 rear end.

YMMV.
 
yea, i dont have any vibes either, 5inches. but seeing as though its a trailer queen, and your fabbing long arms, you might not want to take that chance, especially if your goin to be in the middle of some rough trails..
 
The best way to tell anything is by mocking it up and checking angles/clearance etc...

I pulled apart two XJ driveshafts & slip-yokes today to clean, inspect, measure & paint. I will say that the amount of droop allowed by a YJ yoke is remarkable compared to an XJ yoke. Remarkable enough to wonder if the pinion yoke can allow that much - without clearancing it, adding an offset UJoint, or limiting the droop otherwise.

I've ran a SY rear shaft on up to 5.5-6." I didn't have the pinion angle set perfect so I had a zone (55-65) where I had no joy in the coast or cruise mode. On the gas through that zone was ok. Most importantly I never had a fear of the driveshaft slipping out (even with both back wheels fully off the ground... BTW that's where ya check the 'slip' and 'bind'... flexing up one side or the other tells only part of the story)

I will say that for 231 people, the ugraded output shaft and new driveshaft that a SYE and new shaft brings a strength improvement. A h&t, especially with a front shaft, is less of that
 
tech kid said:
probly gonna run sqaure shafts front and rear.....
Click to expand...
and your worried about a SYE kit???
 
indeed, i didnt catch that. why? i ran my stock shaft with a yj and later wk yoke at 5.5" with no problems..
 
RCP Phx said:
and your worried about a SYE kit???
Click to expand...
cause their cheap, indestructable, and they work. its a trail only rig, so it doesnt really matter. lots of guys are running that type of shaft, lots of slip too...just what works for cheap and is pretty stout

wes
 
tech kid said:
cause their cheap, indestructable, and they work. its a trail only rig, so it doesnt really matter. lots of guys are running that type of shaft, lots of slip too...just what works for cheap and is pretty stout

wes
Click to expand...

Doesn't make sense to me. If you're gonna run square driveshafts you have to have a SYE. Unless you were thinking of a one piece square driveshaft. I've never seen that done and it certainly wouldn't be indestructible with a slip yoke in the transfer case.
 
tech kid said:
cause their cheap, indestructable, and they work. its a trail only rig, so it doesnt really matter. lots of guys are running that type of shaft, lots of slip too...just what works for cheap and is pretty stout

wes
Click to expand...


it wouldnt be any cheaper than keeping the stock shaft, as it would require you doing an SYE?
 
Not trying to hijack this thread but ive seen alot of guys running square driveshafts. If the shaft got hung up on a rock wouldnt you think it would be harder on the shaft to spin on the rock being square? Just curious as to why people run them.
 
people use em mainly on trail only rigs. they are cheap and easy to build., tho ive never done it
 
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