Can anyone tell where this leak is coming from?

[60series777]

First noticed a sizable puddle after a ~60 mile round trip on the highway. Crawled under the truck and saw the drips coming from the clutch inspection cover*:

Looked further up and saw the perimeter of the cover was wet:

As far as I can tell, the highest point with oil was the clutch slave cylinder:

Clutch feels fine and the clutch fluid is full. Head gasket and oil pan looked dry to me.

 

[OSS]

That first picture is your clutch inspection cover. Notice that it has a big drain hole in it - it’s there for a reason.
Check the oil level in your transmission and transfer case. If the transfer case gears are pumping oil into the transmission (very common) then the transmission fluid level will get too high…. and migrate out past the input shaft seal…. and end up in the clutch inspection cover.

That’s just one scenario.
At this point – every seal and gasket on these ancient trucks is due for a replacement, so it’s no surprise at all that stuff is leaking.

 

[60series777]

The shop I brought my truck to confirmed that it is in fact gear oil, leaking from the front of the tranny where the clutch sits.

I don't have the tools/time/skills to pull apart the transmission so I will likely pay someone to do it. Anyone have insight as to how much $$ a transmission re-seal should cost? What about a rebuilt? Wondering if I should consider a 5 speed swap if I'm nearing that kind of money to fix what I have. Truck shifts through all gears fine and everything seems to be working, it's just leaky.

Going to get 2 or 3 quotes from nearby shops this week, but always appreciate the wisdom of the MUD community.