I had low MPG with the factory rear end mated with my V-6, on my truck and decided to change from the Dana 44 3.92 down to a 3.23 gear. I contacted Precision Gear and ordered a Pinion Gear, Ring Gear and new barings for the kit. The kit comes with ALL the shim rimgs you'll need. You will need a GOOD mic to measure the thickness of the shim rings so you don't waste time putting in a shim that's too thick or to thin.
While we had everything apart we took time to clean out the axle tube, you'll be surprised just how much rust and debris will come out. Just ball up some rags and push them through with a broom handle do this several times, like swabbing out a cannon barrel. Use a light to see if you have it all cleaned out. Unless the wheel barings are new, spend $10 more bucks and change those to.
It was an easy change out, BUT you do need a special dial flex mic to get the alignment set just right. When I did mine a mechanic friend helped me and we took a lot of pictures.
Here is the album, hope this helps you.
http://rides.webshots.com/album/570438270cjSEvE
