If it is slinging fluid, like it obviously is, then the axle could be low and since you just bought I would change the axle fluid and if you have not done the seal replacement before, watch a you tube to see if you can do it. I don't see a tear on the inner cv boot, unless there is one I cannot see, so likely just the seal replacement. If the boot is torn or cracked open I would just replace the axle shaft assembly. If you just let this go you are asking for problems. Hell, it's your money not mine, do the rear axle fluid change and do the transfer case fluid and do the trans filter and gasket at least. What is the mileage?