i had some questions a few weeks ago about my 4x4 and i think i have found the problem.my front inner joint is shot.the shaft is not broken but the joint is gone. can i buy just a repair kit or do i need to do something with the cup that it rides in.if so can you buy the cup part or do i have to buy a whole new axle assembly?how do you know if the cup is wore to bad to use again?