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93XJ man. trans w/ 231 TC buying RE 4.5 and 31's....SYE/CV??? yes or no

4

435Mj

NAXJA Forum User
Location
utah
so im getting the 4.5" RE full spring pack. im 90% sure im going with 31X10.5R15 BFG AT's will i need to get a SYE and a CV drive shaft? and if i choose to go with 33X10.5 will that make any diffrence beside haveing to trim a bit? thanks a bunch. i have posted a few other threds you may have read them idk but im really thankfull for the help.

P.S if i need the SYE and CV who do you recomend price is kinda of an issue but will shell out the extra money to do it right the frist time.
 
yep... pretty much anything over 3.5" will need an SYE to combat diveline vibes.

Tire size will make no matter.

Tom woods offers a SYE/driveshaft combo
 
You don't need a SYE, I am at 6.5 with the 5 speed and np231 with no vibes. You can use a 1 inch drop between the crossmember and frame, or a slip yoke from a YJ wrangler might work without dropping the transfer case. The YJ yoke is slightly longer and alows for much higher angles.
 
I am running the RE4.5 lift but I did the bastard rear leaf pack and am not running a SYE. I did put in all new ujoints at the same time as the lift. I have been running like this for 7 months now and have not had any vibes. My truck never see's speeds of about 55 though, I'm running 34 TSL's and no sway bars so I just take it easy in the slow lane on the highway.......

Some day I will do the SYE kit that PORC has for $185
 
jeepboy381 said:
You don't need a SYE, I am at 6.5 with the 5 speed and np231 with no vibes. You can use a 1 inch drop between the crossmember and frame, or a slip yoke from a YJ wrangler might work without dropping the transfer case. The YJ yoke is slightly longer and alows for much higher angles.
Click to expand...
Yeah, you could do that, but I would not want to lower the Trans closer to the rocks. A SYE, is also an extra assurance that you will at least have front wheel drive if your rear shaft decides to part company. You can do it right, or you can do it again.

Rob $.02
 
I have never had any problems, a drive 50 miles a day lifted 6 inchs with no SYE and no dropped transfer case and just the YJ Yoke for 2 years. Get your pinion angle right which your new spring packs should do and your fine. At 6.5 inch's though your stock driveshaft won't be long enough, I upgraded my rear axle to a dana 44 which shoved my driveshaft a little bit more forward and that is why my driveshaft did not need to be lengthend. Your at 4.5 though so you should be fine with just the YJ yoke. The SYE would be nice but I wouldn't spend the money if I didn't have to do it. But that is just me. If you have the money to spare, go for it, it is a good upgrade.
 
At 4.5" w/1" drop and 249 I had bad vibes and had to get a SYE. Mine's a '99 though, and from my understanding the newer ones seem more prone to vibes.
 
OK, it's a bit more complicated then that. With that lift your driveshaft will be on the short side which will probably be the main cause of the vibes (if you have the angles set up right that is). Anyways, SYE will be a very good idea for that setup, but if you don't want to go that route, install everything, make sure the output of the axle and tcase are parallel and then measure how long of a driveshaft you need to insure enough of spline engagement to prevent vibes and to prevent driveshaft fallout on the trail.
 
skeptic_always said:
At 4.5" w/1" drop and 249 I had bad vibes and had to get a SYE. Mine's a '99 though, and from my understanding the newer ones seem more prone to vibes.
Click to expand...

why is there so much varitation between years....i think its 95 back its a 50/50 chance of needing the sye but 96 on its almost manditory. why is that?
 
who knows. There is a 93 XJ in my parking lot with about 7.5" and 34s with no tcase drop, no sye and maybe shims, cant remember. The RE kit comes with a tcase drop and i have driven quite a few earlier XJs with 33s with no SYE, but plan financially for it just incase.
 
rock rash said:
who knows. There is a 93 XJ in my parking lot with about 7.5" and 34s with no tcase drop, no sye and maybe shims, cant remember. The RE kit comes with a tcase drop and i have driven quite a few earlier XJs with 33s with no SYE, but plan financially for it just incase.
Click to expand...

thats makes me hopefull im going to buy one just to be on the safe side i think.....you just never know
 
Kejtar said:
Don't tell me that it has a stock driveshaft....
Click to expand...
WOW!! I have a 94 xj with 7.5'' and i have a s.y.e. AND an extended c.v. driveshaft. I have BARELY enough spline engagement at full droop!!(although I did move my e-brake cables for more slack):shiver: Good Luck!!
 
ok so i went to my mechanic friend today and he literly drew out a picture for me to explane how the DS and my TC works and why im replacing it and i totaly understand now, i know it seems dumb but whatever.....sye/cv all the way. thanks for the help hi-jack away:viking:
 
xj_toker said:
ok so i went to my mechanic friend today and he literly drew out a picture for me to explane how the DS and my TC works and why im replacing it and i totaly understand now, i know it seems dumb but whatever.....sye/cv all the way. thanks for the help hi-jack away:viking:
Click to expand...

Good job on doing yor homework. Wise choice my friend :sunshine:

Rob
 
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