Parts identification near oil pan

[o2fill]

Hi,

First time poster, long-time owner.

I have a 99 pathfinder with 220,000 miles. I have a fairly persistent oil leak which I have tracked to the location in the first image of this gallery:

http://imgur.com/a/H1Ycb

The remaining images (except # 3) show the part from two other angles for context. It appears to be a spring-loaded valve. What is it? Also, I'd be interested in perspectives on what the source of the leak is. My hope is that it is not the main seal but my gut says it probably is.

While poking around under there, I also spotted a loose part (image 3) - it consists of two rubber hoses terminating in open-ended hooked metal tubes. If anyone knows what this is, what it is supposed to be connected to and where it was supposed to be attached to the body, I'd really appreciate it.

Many thanks!

[Hooligan]

At 220,000 miles all signs point to the rear seal. The hose and the two metal thingees are transmission vents. They should be bolted to the upper most bolt on the bellhousing passenger side. Alot of lazy mechanics forget to replace them in their rightful location after reinstalling the transmission. Probably the last time you had the clutch replaced.

[Hooligan]

The thing in the first picture is the clutch slave cylinder. Are you leaking oil or fluid from the slave cylinder? Are you having to add fluid to the hydraulic clutch system or just motor oil?