Is it possible to do the swap without replacing gears? Don't mean to sound ignorant but... in all reality I am 😞 lol

 

Yes, you shouldn't need to re-gear anything unless the axle ratios are different.

This is very unlikely.

If you have an automatic, try to stick to Jeeps with automatics from the bone yard. Automatics typically have a 3:55 gear ratio while manual typically have 4:10 gear ratio.

If you find a stick with one, you might want to grab both the front and rear axles (and the speedo gear).

 

The 2.5L XJs also came with 4:10s to help make up for the missing torque. The local boneyard where I used to live got a lot of the 4-bangers for some reason.

 

is one gear ratio better than the other?

 

3.55:1 compared to 4.10:1 gets you less engine rotations per wheel rotation resulting in less power, this was the ratio used on stock auto 4.0 xjs and other jeeps. If you are running stock size tires and doing normal stuff 3.55 is great. If you have larger tires and want to compensate for the mechanical loss due to your gear ratio being effectively decreased you would want to run a numerically higher gear ratio (4.10,4.56,4.88, 5.13) if you have 31s or 30s 4.10 gears will put you right around the stock ratio meaning similar performance as when it was stock. If you have 32"+ tires 4.10 gears aren't ideal, but they are much better than the stock 3.55 ratio. Keep in mind that if you find an axle with 4.10s you will need to match the front ratio to the rear or your tcase will die if you engage 4x4.

 

Depends what you use your Jeep for. If you are a daily driver and have stock tires, 3:55 net better fuel economy on the road from 30-80 MPH.

If you are planning to lift and put bigger tires on, the 4:10 would benefit you around town.

 

4.0L with 5 speed had 3.07 ratio... 2.5L with 5 speed were 4.10.

 

Fair point. I don't see as many stick 4.0Ls around here.

 

Auto 2.5L had 4.56 as well (harder to find)

 

It all depends on what size tires that you want to run as to what gears you need.

 

Right now I've got 31's when all is said and done I'd like to roll 33's but that'd be as big as I'll realistically go how much would it cost to re gear my front and rear when I get to that? And what would be best for me to re gear to?