wn7186

Hi guys. 1998 k1500 is the truck. Noticed today while servicing my truck that around the outside cv boot on the right side there is a lot of grease in the creases of the boot. Should I replace the boot or just replace the whole axle assembly. Another question this past winter in the snow I noticed a sort of rough almost grinding noise coming from the front end while engaged in 4x4. 4x4 works fine it just started this noise. You can almost feel it more than you can hear it,if you know what I mean. Any advice on both of these problems would be great. I'm more concerned about the noise because I have no idea what it is.