Backlash, a bear if you've never done it.
I would honestly go grab a 8.8, even a 28 spline will be good, and direct swap. If you want a little more challenge, get an expo 8.8 31 spline, and you can get em cheap and with disc brakes.
I would check out all of the tuts in the gears and locker section of TRS. Good info there.