That is a real good one... gotta love it! haha!

 

I ran 30x9.50R15 on mine stock and had no rubbing. I tried for 31x10.50 and the front bumper got in the way.

you will truly like the Rubicon Express kit. RE has yet to make anything bad.

 

iv got a ? whats the diffrecne in the d30 d35 d40 and chyrsler 8.25

 

what year is your XJ? The D30 is Dana 30, front differential. Came in a few different configurations.
The Dana 35, is a piece of crap that will blow up as soon as you go any bigger than 31"s or if you lock it.
The Chryslter 8.25 is a differential made by Chrysler that has a ring gear that is 8.25"
Comprable to the D44 or the Ford 8.8, However the Ford has a bigger ring gear. and the D44 has larger shafts.

Please correct me if I am wrong. this is what I am told.

 

2000 xj sport i saw the front said dana but nothing more and iv got the chyrsler 8.25

 

Dana 30 = poop. Chryslers are good, I got the 8.25 on mine and had no issues. The 40's are the best though, they're more beefy and can handle more.

 

Wow, lots of interesting acronyms floating around in this thread. To the OP (original poster), congrats on your purchase! Yes the 00's and 01's have a low pinion Dana 30 front axle. They also have the trouble-prone 0331 heads, as well as distributor-less ignition. HOWEVER, I know several people with 00's-01's who have not had any problems with them. Take good care of your vehicle, and if problems do arise, well that's what the forums are for.

As for axles, XJ's have never had anything but a Dana 30 in the front. There have been different variations, such as the vacuum disconnect D30, smaller u-joints, and low pinion vs high pinion axles. Spline count has always been 27 spline. The Dana 30 is an excellent axle for the average XJ, and will stand up to some impressive abuse. It does have a breaking point however. Once you get into 35" tire range, you are asking for trouble if you don't build the axle to handle them.

Low pinion D30's are considered less favorable than high pinion D30's. It's ironic that we XJ guys bash the LP 30 so much though, considering that's what comes standard in the TJ's and there are PLENTY of TJ guys that regularly wheel on 35's with their LP D30. But it still stands true that the HP D30 is a stronger, better axle. You are limited to 4:88's however as your deepest gear selection.

As for rear axles, you will see 3 different options on the XJ. Most common are the PATHETIC Dana 35 rear, and the 2 variations of the Chrysler 8.25 rear. The least common is the XJ Dana 44 rear, which only came on select models from 1987-1989 (it was rumored you should look for those equipped with the "tow package" feature).

The Dana 35 has thin walled tubes, a small ring and pinion, and is prone to breakage with anything over a 33" tire. If you have ABS on your jeep, you have the Dana 35. The Chrysler 8.25 came in both 27 spline and 29 spline variations. It is a c-clip axle, meaning it is retained by clips at the spline end inside the carrier. If you break one of these and keep driving, your wheel/tire/axle will walk itself out the housing and leave you on 3 wheels. BUT, the 29 spline 8.25 is a stout axle and with a little work will easily handle a 35 inch tire. Deepest gears available for the 8.25 is 4:88.

The venerable D44 is the most sought after factory rear end by those who wheel their XJ's. Several reasons include; it's a non c-clip axle, 31 spline count, gear ratios available past 4:88 (5:13's and 5:38's for example), and is generally considered the strongest and best option for an XJ on 35-36" tires.

Now, having said all that, when "building" your XJ there are some things you need to take into consideration: what will the primary use of your jeep be? What kind of capabilities do you WANT it to have, and what do you really NEED. I've seen so many people overbuild their XJ for their use and they could have used a lot of that money elsewhere. So many guys get "inch-itis", and you just keep wanting to go bigger (happened to me). However, the XJ is an extremely capable vehicle even in simple stock form. My first mods were a 3" lift and 31" tires and for 2 yrs I wheeled that thing all over Moab UT (no lockers) including Poison Spider Mesa, Golden Spike, Gold Bar Rim, Steel Bender, Hell's Revenge, Fins N Things, Kane Creek, Elephant Hill and more. You will be surprised what just a little lift and slightly larger tire will do for your XJ.

Word to the wise - give serious thought to what you really want to accomplish with your build and build it once and build it right.

Hope this helps.