Was changing the oil in my 1991 K1500 today and noticed this huge greasy mess apparently leaking from the drive axle seal (see pictures). Both sides are leaking. I don't know much about suspension stuff but how big a deal is this? And what needs to be replaced..the whole drive shaft or can just the seal boots be replaced. If just the boots, does the drive axle have to be removed to do this? I've read in other posts that the drive axle can be difficult to remove so am thinking about having someone do it rather than tackling it myself..just want to be prepared before I go in so i don't get ripped off.