GL 450 problem
 

Hey guys...hopefully you can help me out.. I bought a used 2008 GL 450 and it has about 60k miles on it. Just recently I noticed that it's leaking water underneath in small amounts.. Is this normal? has anyone else had this issue. Also I had to reverse back to my house a couple of weeks ago..left my wallet.. and the car will not go over 10 mph in reverse.. is there a pilot on this model? and last but not least.. when I open the door with the car off.. I hear an air pressure sound as the car elevates... is that normal? My first MB so I want to make sure everythings ok!! Help me out if you can

the air release noise is normal, the noise usually happens after youve gotten out of the vehicle and closed the door
the 10 mph in reverse is not normal. i've driven much faster than that in reverse in many benzes and ive never encountered that one. id be curious to know the cause of that.