Rlmx

Have a 91 XJ 5 speed manual, Dana 30 & 35 @ 3.08 ratio.

Found a 91 XJ automatic with a "Dana M30/181MM Front Axle", a "Corporate 8.25 Rear Axle" (Chrysler), and a "3.55 Rear Axle Ratio." For the sake of the conversation, "FS XJ" = the "for sale XJ." The price is $800. FS XJ has 300,000 miles on the odometer. My XJ is at 200,000.

Can I swap over the FS XJ front and rear axle/difs to my XJ? Is the design of the front and rear axles completely independent of the accompanying transmission? (OK, Maybe the 3.08 ratio is better for a manual transmission vs. a 3.55 IDK?)

The primary difference between my XJ and FS XJ is that the latter has an automatic transmission, and lots of nicer bells and whistles. There are many other parts on FS XJ that will help me out. Seats are in much better shape, alloy wheels, roof rack (my XJ doesn't have), the dash is in excellent shape (realize that is a two day, frustrating job, but I want my Jeep XJ to be nice!).

Also, think I found the answer to this, but would like a confirmation... FS XJ has a "Lock-Up Torque Converter." Can't swap that over, correct? That is integrated into the automatic transmission, right? (Unless maybe I swap the automatic tranny for the manual. AINT no way!)

firebane

Pull em, swap em, and drive.

The 8.25 will be better in the rear and the 3.55 gears will be better for the 5spd.

00t444e

The 8.25 is much stronger and the 3.55 gears are better. It will be a direct swap.

SexyDexy

I am pretty sure the d35 has different u-bolts than the 8.25, so you will need those.

But which ever direction you go, just make sure the gearing is the same for both the front and the rear diffs... or the xfer case will blow when you put it in 4wd and go.

kyle96xj

The 3.07 or 3.08 gears in your axles is best suited for the manual with stock size tires, if you have taller tires the 3.55 gears will be a nice upgrade and give you more torque to match the tires. As for the torque converter you're correct that you can't use that with your manual transmission, it's part of the auto trans.

freegdr

5th gear on manual is basically overdrive...

XJwonders

Also swap over driveshafts cause the 8.25 pinion is longer

Battle

I, along with a bunch of other people on here, have done the auto axle swap to get 3:55 gears. Ran them with 31s. Great combo. I also liked 4:11s and skinny 33s.

You'll have zero issues as long as you get 8.25 u bolts and ensure the driveshaft length is right. At that mileage though, I'd expect to replace bearings and ball joints.

I think stock stick gearing is 3:07 by the way. It's only good for lazy highway cruising and highway economy. It's terrible for everything else. I have them on my current stock rig, but want to go with 3:73s and 29 or 30" tires. Should be fun.

Rlmx

Thanks to all for the input!

Battle, could you please expand on that?

The first thing that comes to mind is that both are two door models. But that may be a goofy way to look at it. I am not sure. Absent knowing the part number, or I guess just measuring something, how will I know?

cruiser54

The nose of the 8.25 is longer than the D35. Unless you're lifted a bit, the original driveshaft could be too long.