Oil Pan Question

Can the v6 oil pan be changed without removing the engine? I have had an oil leak for some time, I thought it was coming from off the top of the motor I pulled the doghouse and there was no sign of an oil leak anywhere. I backed the van into the yard and it was on an incline after about 10 min. I saw about a quarter of a quart of oil on the ground,I got down on the ground and looked under the engine and about 6 inches back from the harmonic balancer on the oil pan oil was dripping down and running on the ground ,I could'nt tell if was a hole in the oil pan or the pan gasket was leaking. back on level ground it only leaks when the van is moving or just after I park it after a run. does anyone have an idea what it could be?

Have you taken a close look at the oil cooler lines?