04 2004 BMW X5 Axle Assembly - Driveshaft & Axle - EMPI, First Equipment Quality, A1 Cardone, USA Industries, Front Left, Front Right, Rear - PartsGeek

Figure about $200 shipped for the axles. Comes with the axles nut. You'll also need the left and right side differential seals. And you'll need new diff gear oil. 75W-90 synthetic is fine.

Remove the skid plate(s). Remove wheels. Remove brake calipers and rotors. Remove axle nuts. Disconnect the ball joints for the lower control arms. Swing the strut assembly out of the way and pull the old axles out of the diff housing. This requires some effort and usually a BFH. Remove old diff seals. Install new diff seals. Install new axles remembering to remove the red plastic protector on the seal. Again, a BFH usually makes this easier. Re-install everything else. Drain old diff fluid and refill with new.

The only hard part is popping the ball joints. If you don't have the tools or experience I suggest having a shop do the work for you. They can be a bitch if they've never been off before.