I recently did a brake overhaul on my truck...well almost complete overhaul, master, rotors, calipers, steel braided brake lines. I was thinking that my left rear wheel cylinder was faulty and leaking only to find out it wasn't but what I did find was puzzling. I found black grease looks to me like axle grease on my brake shoes. It is my thinking that the rear wheel bearing has taken a dirt nap...but after putting the brake drum back on and cleaning it up it hasn't leaked since. Can anyone offer any feedback with regards to the mystery grease on the shoes???

 

Could be your differential vent was plugged and pushed the gear oil out

some how came unblocked just keep an eye on it.

 

check and make sure that the diff oil has not gotten
so low it doesn't leak now.

 

Ok I'll check it out today and clean it to make sure