Ford Repair: cv joints, cv shaft, cv joints

Question
how hard to change cv joints on 97 ford 4wd?

Answer
I'm going out on a limb here to assume you mean a Ford F150.  If I guessed wrong, my answer may not help you.  You'll need to remove the wheel, the large nut securing the cv axle to the hub, and the lower ball joint.  Most often the cv shaft is rusted tight to the spindle and has to be pounded out with  lot of force.  From there, remove the bolts holding it to the front differential and it should slide out.  Reverse procedure to install the new axle.  Hope this helps,
Jason