How to tell rear ends?

New to the jeep thing...had Big Broncos for a long time...I got a freebie 1990 xj tryin to figure out what rear end...gears...axles...I cant find any tags on it. It runs and drive ok, But goin to start building on it. So what Im askin, Is how to tell what gears,rear end and axles are in this thing?

not to sound rude but. home page of the forum. FAQ is a must read. But in regards to your question.
http://www.naxja.org/forum/showthread.php?t=101249

Thought I'd share some information on how to identify a Dana axle.
Useful when trying to identify axles in a junkyard.

Every Dana axle has a "Bill of Material" number. It is specific to the axle/vehicle/application. There are a series of #'s stamped on the axle assembly/housing.



The important # is the "Bill of Material" number on the "long tube"
Typically a 6 digit #.

With that number, you can go to the Dana website and enter the Bill of Material number.
Use the link below and enter the number.

http://www2.dana.com/expert/wc.dll?cvsp~deabill~2~

Here's a link to the main page

http://www2.dana.com/expertforms/demenu.aspx

It will list the specifics of the axle - may even have detailed assembly drawings of the axle.

Here's another link I found at therangerstation.com - has the entire description of Dana axles cataloged by Bill of Material number.

http://www.therangerstation.com/tech_library/Dana_BOM_numbers.html

Hope this helps.

yeah i looked at the home page...just thought someone would have a "quickie way" just by size or bolts that kinda thing...

begster had what i was looking for...thanks

From your year, you have a Dana 30 front end, and a Dana 35 rear end.
Don't put any money into the dana 35, put a new one in it.

i see that some late 80s xj had 44s....thats what i think ill look for

And not a new D35.. go with a D44 or better.

are the d30s ok in the front?

D44s are better.. lol

Sorry, thanks for pointing that out xxmidianxx, I meant to say swap it for something else. You can do a d44 which will be a direct bolt up, or you can do some modifications and through a Ford 8.8 in there. Both are popular, but I think the D44 is the better choice, don't have to worry about spun tubes as much or the C-clip shafts.

D30's are a toss up, I know some people who run beefed up d30's with alloys and 36's, and I have blown up my spider gears on 32's. I'm now replacing mine for a D44. Follow this link, it will help you with your decisions.
http://www.naxja.org/forum/showthread.php?t=101343

What set up are you planning on running, are you light on the skinny pedal or go balls to the wall?

Edit: Midian has the idea.