So when I go to my car after it's been parked, I see oil stains on the ground under the front passenger side. So I jacked it up and saw that the leak was coming from one of two (extremely rusty) metal line that go into the radiator on that side. Upon closer examination I could see that the oil was coming from a small gash in the pipe. The internet tells me that they are called oil cooler lines and they run from the transmission to the radiator, which is a concept that blows my mind. For a clearer view of what I'm talking about, the part can be
seen here and
here .My questions are:
1. What is the concept behind this system? I was stunned enough by the fact that oil is going into the radiator but to find out that the other end goes into the transmission- huh?
2. Are there any tricks involved in replacing the lines? I assume I'd have to drain the oil before replacing but would I have to drain the transmission too?