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CV shaft & SYE for 31"s ??? please help !!

K

korr2236

NAXJA Forum User
Location
Centennial, CO.
hi guys~~~

this is my first post here..............

i've searched for days...and visited 4WHEEL PARTS(in Denver, Colorado).....but ... i still need your help for my decision.

i have a stock 2001 XJ.

4.0 litre / automatic / 2H-4H-N-4L. ( do you call these AW4 and NP231 ???)

i'm thinking about < 31" tires with Rubicon Express 3.5" lift kit >

my questions are.....

1. am i gonna have drive-line vibration and have to buy CV shaft & SYE
when installing even 31s with RE3.5" lift kit ?
( if so, i'd better go for 32s, right?)

2. do i have to change ring&pinion gears?? if so, which ratio do you recommend??
i go off roading 1~2 times a month....and moderate level...
(if so, i'd better go 32s, what do you think?)

thank you guys~~~~~~
 
Last edited:
AW4 is the automatic transmission.

2H-4H-N-4L is NP231

the tire size IS NOT what causes driveline vibs. it's the drive line angles. at 3"+, a SYE is recommended. it's not necessarily "required", but definitely recommended. if you don't install a SYE, you'll most likely have to shim your rear axle to correct your driveline angles.

first it would be good to know what gears you currently have. there should be a little tag on the front/rear diff cover. most likely you have 3.55's. it'll be fine, but you'll loose a little bit of power. most likely it won't be worth re-gearing though. if you plan on keeping 31's/32's for a long time, then it might be. but if you plan on going bigger in the "near future", then wait and regear accordingly when you go bigger.
 
yes, i have 3.55's.
i'd better go 32's with 4.10 gears & SYE...then...i guess....
then i don't need to install CV shaft if i install a SYE????
thank you very much, scorpio_vette ~~~~
 
korr2236 said:
yes, i have 3.55's.
i'd better go 32's with 4.10 gears & SYE...then...i guess....
then i don't need to install CV shaft if i install a SYE????
thank you very much, scorpio_vette ~~~~
Click to expand...

No youd still have to get a new shaft with installing the sye,an sye is a Slip Yoke Elimator and your current drive shaft will no longer be able to slip in the transfer case with an sye installed.
 
korr2236 said:
i'd better go 32's with 4.10 gears & SYE...then...i guess....
then i don't need to install CV shaft if i install a SYE????
Click to expand...

You are so easy about regearing, but you want to save on CV and SYE ?
Is it a trail only rig ?

Have you checked the prices ????

CV+SYE = 400-500 parts

regearing = ~400-500 parts + ~400 labour.

After installing SYE you will need to shim your rear axle, shimming without SYE might not help at all.

I run 3.5 RE on 31", manual, 3.07 gears, teralow.
Tires rub occasionally on a trail.

Andrey
 
korr2236 said:
yes, i have 3.55's.
i'd better go 32's with 4.10 gears & SYE...then...i guess....
then i don't need to install CV shaft if i install a SYE????
thank you very much, scorpio_vette ~~~~
Click to expand...

you will need the matching driveshaft to go with the SYE.

just curious...........why do you keep thinking that bumping up to 32's will fix your problems??? you can run the gears you have now. it'll be fine for a while, that way you don't need to come up with the money for gears and install right now. you can then decide to do it down the road if you want.

right now just get the lift. get the SYE+driveshaft. get the tires, and then drive it for a while.
 
thank you very much, scorpio_vette,Slonopotam and jeepxj97 ~~
you helped me a lot ~~

i made an appointment on 28th of Aug. at 4Wheel Part.
i'll do
RE 4.5 kit / new shaft&SYE / 32's on 15X8 black rock crawler(steel..but cheep..) /
no gearing right now /

i'll post my lifted-up xj soon~~
 
scorpio_vette said:
you will need the matching driveshaft to go with the SYE.

just curious...........why do you keep thinking that bumping up to 32's will fix your problems??? you can run the gears you have now. it'll be fine for a while, that way you don't need to come up with the money for gears and install right now. you can then decide to do it down the road if you want.

right now just get the lift. get the SYE+driveshaft. get the tires, and then drive it for a while.
Click to expand...

I added an RE 3.5" lift on a 97 XJ. I had severe rear drive shaft vibration. I shimmed the rear 2 degrees. It barely helped, if at all. I got the Advanced Adapters SYE and Tom Woods CV shaft from Rusty's for Just under $500. It was a perfect, high quality kit and comletely solved the problem.

I also added 4.10 gears (31" tires, 4.0, AW4, NP231). It is a perfect match. I love climbing with this set up. I can ease up to a severe incline, in 4 Low, and just a littlle throttle (barely more than idle) and on up it goes. It's a climbing machine!
 
Last edited:
korr2236 said:
can i see some pictures of your XJ please?
Click to expand...

I am not sure whom have you asked, but here are mine. Search for a blue 2door. Most of them were taken after I lifted it.

http://slonopotam.no-ip.org/
 
Cancel the 4WP appointment...I know we've got at least one member on the board who works there in Sales, but 4WP is one of the last places I would allow to work on my junk. If you ordered the lift from them you can probably find a better price from some of the NAXJA vendors.

As for CV and SYE, it's very likely that you'll need them on your rig. If you have no plans in the future to upsize the tires, then 4.10s will work fine. If you may end up larger in the future, stay with the stock 3.55s until you go bigger. If you do such, you may also want to locate a hi-pinion D30 from a 95.5 or later XJ and install that after regearing.
 
Just installed RE 3.5" and 31" tires. Only vibration I get is between about 15 and 25 mph.
Question for all. Should I try the transfer case lowering kit to eliminate vibration or go straight to the CV and SYE?
Also, at higher speeds when I let off the gas, I get a growling/grrrrrrrrrrrrrr sound, what's that all about? Help.

Korr2236 Here is a pic for ya. I can send more

KodiakXJ
IMG_1387.jpg
 
KodiakXJ said:
Just installed RE 3.5" and 31" tires. Only vibration I get is between about 15 and 25 mph.
Question for all. Should I try the transfer case lowering kit to eliminate vibration or go straight to the CV and SYE?
Also, at higher speeds when I let off the gas, I get a growling/grrrrrrrrrrrrrr sound, what's that all about? Help.

Korr2236 Here is a pic for ya. I can send more

KodiakXJ
IMG_1387.jpg
Click to expand...

is it just me, or does it look like the front is lower than the back???

if you can afford it, then go straight for the SYE. the growling you are getting is from your rear driveshaft being at a bad angle. when you are driving, and suddenly let off the gas, your pinion turns down a little. which brings your u-joints pretty close to binding since they're at such a bad angle. if you don't fix that soon, you'll start eating u-joints pretty quickly.
 
Thanks for the info!
Will be measuring driveshaft and ordering CV and SYE today. The rear does sit as bit higher. I may need to adjust, what do you recommend to level it out a bit?

KodiakXJ
 
try some pinion shims in the rear end , and drop the tcase 1/2 in with some washers or something if you dont wanna shell out cash right away, but if you have the cash its the best solution.
 
KodiakXJ said:
Thanks for the info!
Will be measuring driveshaft and ordering CV and SYE today. The rear does sit as bit higher. I may need to adjust, what do you recommend to level it out a bit?

KodiakXJ
Click to expand...
I had the same problem with my 98 after 3.5 . I tried a rustys 1 inch tranfer drop it helped a little but didnt get rid of all the vibration. So I have a RE hackntap and CV driveshaft to go on. I added some weight in the rear for a cpl months ( bags of concrete mix) and it settled down
 
measure from the ground to the bottom of your fender flares. how much difference is there??? if there is over 1/2 difference between the front and rear, you could put some coil spacers in the front.
 
scorpio_vette said:
is it just me, or does it look like the front is lower than the back???

if you can afford it, then go straight for the SYE. the growling you are getting is from your rear driveshaft being at a bad angle. when you are driving, and suddenly let off the gas, your pinion turns down a little. which brings your u-joints pretty close to binding since they're at such a bad angle. if you don't fix that soon, you'll start eating u-joints pretty quickly.
Click to expand...

Buy some ACOS to raise your front, your lines are outta whack cause you are no where near level front to rear.
 
I just put an RE 3.5 inch super flex on my Cherokee and I love it!! I have a post on here trying to figure out why the guy that put the lift on my Jeep left my TC drop on with the SYE. I have the 3.55 gears and I'm running 255/70/16's and the Jeep gets down the road just fine. I drove it to Little Rock AR from PA and got 23 mpg. so I don't know if you really want to regear right now. You might want to drive it with out gearing and see how you like it, it just might save you some money. If you do decide to regear, and this is a question for the other guys that have been answering you, are the gears in the back of the Essentials (Quadratec) catalog any good? They have gears from 3.55, 4.10, and 4.56 for $219. I think that is a good price for gears, but are they any good?
 
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