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8.8 in MJ's

M

MJ1990buildup

NAXJA Forum User
Location
Chesapeake Beach
Well i am finally getting around to upgrading my rear axle and understand that the 8.8 is offset by a couple inches, most guys i know running them in cherokee's have an SYE and i was wondering if anybody had to put one in there MJ

i know this is a hot topic so if anyone can offer a different axle i would appreciate it, welding is not a problem
 
Last edited:
okay, I just saw this on the Pirate board, it's under a YJ:
Overhead_view_x_m.jpg


he's running a CV, but with that short wheel-base that's still a good bit of angle. I really don't think you would have a problem on an MJ, but I'm not basing that on experience.
 
they are offset on Explorers but when put into a XJ that is no problem. I did it. A short wheelbase MJ "might" be more of a problem but I suspect the WB is longer than a YJ. It's a great axle to use. Danno
 
short wb MJ is 113, long wb is 119 or 120, so it's at least a foot longer than an XJ. i think his primary concern though is doing it without a SYE and double-cardan shaft. most (all?) MJs with 6-8 inches of lift haven't needed an SYE because of the better driveshaft angles.
 
from a YJ 8.8 swap
The pinion is offset a whopping 2-3/16" to the right of center, compared with 3/4" for the Dana 35. This additional 1-7/16" of offset on a 17" driveshaft makes a horizontal angle of 4.8 degrees at the pinion U-joint. This isn't a big deal with a stock, single-cardan driveshaft, but with a CV driveshaft, that kind of angle can potentially eat U-joints and cause driveline vibrations. M.O.R.E. claims this hasn't been a problem in their experience. We'll see.
Click to expand...

swap here: http://www.jedi.com/obiwan/jeep/ford88.html

It sounds like a single cardan shaft, like your stock MJ, is actually better for having a slightly offset rear axle.
 
my main concern was with the SYE, hadnt really even thunk about a CV driveshaft


hey brett, quick question, why do they call the yoter rear end 8"s when i know the ring gear is over 9" tall
 
i was considering making a leaf pack for the rear and matching it with the front, but i think i'm just going to go with whatever SOA gives me

i'm assuming if you offset your perches that would help the pinnion?
 
MJ1990buildup said:
i'm assuming if you offset your perches that would help the pinnion?
Click to expand...

Offset the perches? :dunno:

Jeep on!
--Pete
ComancheClub.com
 
Do you mean shifting both the perches over a couple inches? I'm confused. Wouldn't that shift both tires the other way, making one stick out and the other rub the bed? :dunno:
Jeep on!
--Pete
 
BrettM said:
if he meant rotating, yes, rotating is good. if he meant shifting sideways in order to center the pinion, bad idea.
Click to expand...

not so that the axle would be shifted

only that the pinion angle would be adjusted


would this be better than keeping a 90* pinion angle?


and by this i mean perches would be welded square on top of the axle
 
Ahhh, that makes so much more sense now. :D
As I understand it, with a regular driveshaft (not double cardon like the front shaft), the angle of the lower U-joint should be close to the angle of the upper U-joint, regardless of what is parallel to the ground. No wait, I think it needs to be a couple degrees further down, right? To account for the pinion rise that happens when you step on the gas? Not that I should be the one lecturing on this. I just used the Bronco pads and my shaft points directly at the t-case. BAD!! I eventually plan to add a new double cardon shaft to make it right, but in the meantime, I've gotten lucky with very light vibes (on a vehicle I don't drive much).
Jeep on!
--Pete
 
technically with a 2 u-joint shaft (no double cardan) the angle on both joints is supposed to be the same, and a few degrees down to account for axle wrap is probably a good idea.

now what I've seen in experience is that with new u-joints a variety of "wrong" angles work just great. currently I have my pinion pointed almost directly at my t-case (2 joint shaft) and NO vibes. my buddy with a K5 blazer actually has his pinion pointed about 5 degrees above his t-case (2 joint shaft) where it should be about 15-20 degrees below. he had vibes with it pointed right so we flipped his shims around and it is totally "wrong" but works perfectly.

one big thing is that u-joints will often give vibes or self-destruct within a few hundred miles if you change the angle on them. I've seen this happen in at least 5 times in at least 3 trucks. any time you change your angles (more than a degree or two) change your u-joints, it only costs about $25 for a pair of spicers.
 
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