Symptoms of rear axle leak

I just got my rear axle leak repaired and the u -joints replaced. also got my break pads replaced as well. The day after I got it replaced, I have been hearing a small hissing sound intermittently every free seconds. It almost sounds like something is rubbing. I looked under the car where the leak was in the rear tire axle and it looked pretty moist as if it maybe still leaked … or it could be reside from before; not sure. Can anyone inform me of what this hissing sound could be coming from based on these repairs… ?

Thanks – btw the car is a 2000 Ford Excursion

The brake pads will remain in contact with the rotors when the brake pedal is released and the slight drag can sometimes be heard when rolling slowly with the windows down.

What was leaking? An axle seal or the pinion seal? How many miles on the vehicle?

not too sure… I’m not a big car guy. All I really know is the leak was inside the rear tire well… and they said “axle seal”… Shops closed till Monday but I got to go out of town so I was trying to make sure it’s nothing too serious. Trucks got 200k miles. Never had any problems other than some minor stuff. Engine runs smooth etc. The original reason I brought it in was because it was making prtty loud crankng/grinding noises when I was turning right. I guess they fixed Ujoints and said my pad was “frozen up” in the front… The hissing noise that I am referring to seems to be coming directly under the pedal area under car… it isn’t loud at all, sort of sounds like a frequency wave from radio but it is def. coming from car…