Chevy has a TBS on this:
# 15-00-89-004A: Information Regarding the Differences Between Leakage and Seepage - (May 22, 2015)
Can be seepage from an upper component, looking like a seal leakage problem. Replacing a seal is not easy, vehicle blocked up, wheel removed, brake caliper removed and hung safely away, Don't forget the ABS plug.
Rotor, lower ball joint broken free, 185 ft-lbs on the axle shaft, have to have means to keep it from turning, impact wrench is nice to have. Then in road salt areas, that hub bearing will be frozen to the axle shaft splines, lot of guys gave up on this, helps to have a huge puller to push that axle in, but carefully, can wreck the hub bearing.
Strut assembly is moved out, on some vehicles, just remove the darn thing to free that side of the half axle. Other side is held in by a C-clip, and believe me, that slip in a lot easier than they snap out. Fluid from the transaxle will leak out, have a pan handy or a heck of a mess to clean out.
Drill a couple of holes, heck even four, use at least #12 sheet metal screws to evenly pry out the old seal, good to have a seal installing tool to put the new in in straight, angle it, will wreck it. Like a nice coat of RTV so he outer ring doesn't leak.
Would say, not a job for the timid, my boys and their friend tried it, and yelled DAD!!!
If you wreck the boot on the ball joint, have to replace the entire control arm on this thing.