Have a 96 XJ 4.0L Automatic. Stock 3.55 gearing. I know that the 2.5L came with 4.10 gears. Are my carriers the same where I would just be able to do a gear swap (i'm only running 31-32's and it's my DD), or would I also need to swap carrier/other parts?

 

Dana 30 needs a carrier,8.25 does not,& Dana 35 not sure.With 31's you are okay with 3.55's.I run 33's with 3.55 & I'm fine with performance.You don't really need to do a gear swap untill you go to 33's.It's kind of a waste of money if you plan to only run 31's.I'd keep a eye out in the JY's & find a set of 4.10 axles.It's alot cheaper,plus,one weekend you could install the rear end,then the next w/e-the front.1 1/2 hour per axle.