explorer 97 150000 miles make clunking noise with sharp right or left turn. when raised up car front end seams tight. just replaced hub on this side 10000 miles ago. could this be an axle and how hard to replace

 

I'd check for any looseness in the front u-joints then the axle is likely. I would say it's medium difficulty replacing but if you replaced the hub it shouldn't be beyond your doing as long as you have a decent set of tools. Be sure you find the correct damaged part before you buy the replacement though. Different things can go wrong in a 4 wheel drive axle. (Usually the most common is people not realizing that the front gears on some models aren't always matched to the rear axle gears - so you can't turn on the 4 wheel drive on dry pavement without the gears working to destroy each other).