I heard 4.88 and 35's is similar to stock but I have 5.13 and 35's and glad I didnt go 4.88's. Its still slow enough with 5.13's.

 

Let me start out this way, the advice on having someone install the gears is really good. The concept of changing the gears is not all that complicated, but actually doing it requires a lot of patience and an over developed attention to detail, which rapidly deteriorates as patience wears out because the project is taking way longer than planned because you can't seem to get it just perfect. Therefore, take it to someone with experience. If you want to do it yourself, I suggest finding someone skilled to show you how to do it, and have him help you the first 500 times or so until you get the hang of it, and then do it yourself. Might not be that bad of an idea to do, it is, after all hard to find a good "rear end man." With all that out of the way, I am a mechanic, and have worked on a good number of diffs in my time, but I hate working on them because the frustration level escalates and they require so much time. I have a buddy who does pretty much nothing but diffs, and I just let him do it.

Re-reading the original question, everyone, myself included seemed to jump on the do it yourself thing, if someone already answered and I missed it, sorry for overlooking. There are couple install kits that you can get. Basically the difference is that one has bearings and the other doesn't. Do you need new bearings? Yes and no but mostly yes. The thing is you have to pull the bearings off of at least the pinion, and maybe off the carrier (depending on the diff). When I do it myself, I need the new bearings. I have a tendency to bend, crush, or destroy them when pulling them off. My buddy pulls them and reuses them as if it were no big deal. He, generally speaking, doesn't need the install kit with bearings, assuming the bearings are still serviceable, i.e. are from a relatively new and un-abused vehicle. However, he will usually make the call based on his client. Does the guy need the car because it is a daily driver or is it a trail or track only vehicle that is used to down time? On daily drivers he won't do the install without new bearings in the kit. On cars that can experience down time because he damaged the bearing and now has to order another one, he will do it without. So, to determine which install kit you need, base you decision on who is doing the work and can you experience and extended down time. Chances are you don't actually need the bearings, but for the few bucks that you would save, I recommend staying on the safe side and just getting new bearings at the same time. If you didn't actually need them in the end, sell them or keep them around as a spare for the next gear swap.

 

Difficult yes...but NOT impossible....RCJeep and myself have done it on jack stands in the garage....though if you read my write up, yes we both had to either construct or obtain some heavy duty flange wrenches to hold up to the 200+lbs to crush the sleave...true, it is a PITA.
If one has a decent mechanical understanding (I'm not a mechanic at all) and is able to read over the process and understand it, than it can be done. When researching this online prior to attempting it myself I must have read 5 or 6 full detailed writeups...but not specific to the newer JK axles....and read each one 10+ times before I felt confident enough to crack it open....but really, once you've done it, you step back and say "you know...that wasn't that bad"

Oh yeah...and you've got this forum as a great resource with guys like RC and RedNeck with a wealth of knowledge to help out

 

im pretending on doing it with a frien that knows allot of electronics a mechanical but the thing is that its not the money its just not easy to find someone to do this very good over heare, or maybe it is but who knos whos goood, get it.

 

I spent 2-3 months reading, researching, reading and researching gear changes. There are so many good resources on the web for that by the time I cracked open the diff cover, I knew every step in theory. I did spend alot of money on tools for the job, but I like having excuses to buy tools and I still have them for future gear changes for myself or friends (I owe my buddy any kinda works he wants or needs). If you're gonna do it yourself, buy/rent/steal/beg for/or borrow a case spreader. That was by far and away the biggest pita, getting the carrier in and out 7 times (without buggering up thin shims) before I got a good pattern.

Blacknorthern has an excellent writeup on this forum. Take a read and decide for yourself if you wanna do it.

 

Yes....that would have made the job SO much easier. I ended up destroying any shims thinner than .010"...but by that time I'd found the sweet spot and went to a local shop to hunt through a bin to find shims that were already the perfect size...ie. one shim per side of the appropriate thickness, after that it was not bad at all for final assembly...well, except that damned crush sleave
Or another option is to have your shims machined at a shop for you to the appropriate thickness you determine...