I hear everyone saying that if you are running 33's daily you should regear and swap axles? I dont get why? Im running 33's right now daily and i have been for the last month and a half with no problems. My jeep is an auto. I know some of the posts say if your running with a manual. But i dont quite understand the whole regearing and swapping axles. Can someone explain this to me?

manual trannys have a higher gear ratio stock then the autos did, and the dana 35 rear axles aren't so hot and big tires like to break them in short order.

no need to swap axles i dont get that part

But the reason you regear is to keep your jeep in its power band(close to factory gear ratio)

when you upgrade and make your tires larger it takes less revolutions per mile to turn them. So you jeep will then have a noticeable drop in rpms while driving at the same speed you used to. (special highway) and it causes your jeep to work harder.

Basically your jeep has a power band if you are not in that power band(rpm range) then your tranny will always up and downshift funky. and you get a lose of power and gas mileage

I run 33's with 3.07 gearing and on the highway i can no longer use 5th gear as 4th gear puts me at 2200 rpms for 70 mph... 5th is to low and the engine boggs down bad.

i need to re gear. But you want to stay in your power band as much as possible. so you want to get 4.56's for 33" tires on an auto. and for a manual 33" tires need 4.10's

sorry if that is confusing lol its late

The dana35 can handle 33s with lsd or lunch box locker with mild to medium wheeling and stock gears.(3.55 and numerically lower) Thats what I was running and did quite abit of of medium duty wheeling quite often and never had any problems. Now I have a dana44 casue Im going with 35s and 4.56 gears.
The dana35 is one of the weakest links on the XJ. If you dont do much wheeling then youll be fine with 33s.
When you go with taller tires, your mpg drops along with the power. You re-gear to gain that back.

x2 you're gonna want 4.56s with your auto tranny and 33s. And you may want to think about getting the 8.25 29 spline axle out of a 97 or newer xj. its a direct bolt in and a lot stronger.

I too have a 5spd 3.07's and 33's. No problems for me but I will regear when I swap out the rear axle and add lockers.

Well i dont do much wheeling really. But see i swap out from 33's to 31's sometimes. And if i do go wheeling i wouldnt be able to keep the 33's on cuz i dont have my fenders cut enough to flex alot. But i plan on cutting them. So if i run my 33's daily i should prolly get 4.56 gears? How much can i pick them up for? Or what about the rear end out of a 97 or newer? would i be fine with that? Im new to the gearing. Sorry.

how do you go about regearing? is that some kind of kit or something? sorry if this is a stupid question but i'm legitimately ignorant about this.

To regear you need a new ring and pinion (which are located in each of your differentials)

Not to hijack but I was wondering if I should regear when I go to 30x9.5 on my chrysler 8.25 3.55 gears auto trans

I wouldn't worry about it. 30s are not very big at all. I have 33s on stock gears and don't complain too much. You may notice a small difference. But I don't think it'll be enough for you to want to drop $500 on gears, not including the time to actually put em in

Sorry to bump this but I have a 91 XJ Briarwood 4x4 and I'm putting it on the RE 3.5" lift and wanna put 32x11.5 Cooper STT's on it. I'm pretty sure I have a Dana 35 rear axle and was wondering if I need to regear it. I found a Dana 44 for $100, Limited slip, 3.73 gear ratio. Would I be better off running that? I'm only 20 and really new to this. Just thought I'd ask for input. I appreciate it!