transfer case is slippin in 4wd i haven tore it apart yet but wat is the best way of fixing this i say sumethn about an upgraded front output gear if thats the frob how much thay run in price

What do you mean by slipping in 4wd?  That sounds more like a transmission problem then transfer case.  The t-case doesn't have a clutch to slip.

its the front output shaft it makes loud poping noise under load and front wheels stop pulling

That makes more sense.  I would pull the front flange off and see if it is the t-case that has a stripped output shaft or if it is just the flange.  Then go from there.

You might also want to put your front end up on blocks, lock the hubs and make sure everything moves smoothly up front without issues.