So just got my jk a couple weeks ago. Put it up on a lift to see what kind of conditions its in and come to find previous owner never changed any fluids other than oil. So spent the day changing all the fluids. pulled the rear diff cover to find first i have a 3.21 gear ratio. And some idiot has taken apart the rear diff and put it back together wrong. Sorry don't remember names of the components. I'm a generator mechanic so still learning how to work on everything past the engine. But had a mechanic look at it while i had the cover off. If you look at the left side where the clamp is holding the axle and the bearing in you'll notice the gap is all jacked up but its pointless to fix unless i buy a rebuild kit. and its pointless to buy a rebuild kit since i am going to regear it anyway. Atleast the backlash wasn't bad. So hopefully it doesn't actually break before i can afford new gears. but if anyone would like to donate a bigger gear set. I won't complain.


Atleast it looks like the last owner never offroaded it at all so all damage to the bottom that comes will be from me.

Oh and whoevers idea it was to run the exhaust 2 inches below the tranny drain plug is an A$$hole. Had to cut an 17mm allen key and weld it to a 17 mm box wrench to get the drain plug out. They do that crap just so you take it to them for services.

 

Hahaha yeah that drain plug is a pain I bought a short bolt and flattened the sides. Gripped with a visegrips and was good to go. Take that 200 dollar transmission service! Hope that rear end holds up for you.

 

Yeah I did all my fluids a couple weeks ago and the transmission was definately the biggest pain. I bought a coupling nut and cut and grinded it. It worked fairly well. Hopefully now that I have that cut the next time will go quicker.

I didn't bother opening up my rear diff. Maybe I will next time...

 

I almost bought a 4.10 gears for the rear off a guy on here. There's a few guys on here selling them. Under $100 for the gears, but the install is what I can't afford.

 

why how bad is the install? I will be doing it myself. Being military i have a auto craft center to work at with lifts tools, and ase mechanics. and one of them was atleast able to point out whats wrong with the diff and explained how to repair it. Unfortunatly the ase mechanics don't do the work. they just sit there and tell u what to do. but 6 bucks an hour and a hands on walkthrough. can't complain

 

I am not seeing anything wrong with the diff and setting up gears is more than just changing the ring and pinion, there's alot of measuring that goes with it and some special tools needed.

 

I have access to all the tools. The shim pack on the left side isn't fully seated. just looked at the pics again and realized that i centered the photo so you can't even see the shim and how it is not right. my bad. it is a very small amount that it is off. prolly like 1-1.5mm. and did i mention its a 3.21 set. thats reason enough to replace it.

 

If the shim pack isn't fully seated, how can the backlash be good?

 

well its not wearing like the backlash is to far out.

 

Swapping out gears is the one thing I wouldn't do unless your extremely confident in your abilities. If they're not dialed in exactly then lets just say you'll be having a shitty day. I went to Crazy Ed's in Colorado Springs and he did a great job on mine. Well worth the hefty price for sure. Plus he offers a one year warranty for that extra piece of mind.