On my last couple of oil changes I noticed the underside of my 77 from the front of the engine to the rear of the tranny was all wet with oil. Couple of drips here and there. I'd wipe them, the drips, and look around for the source. Couldn't find it. Because there seemed to be more dripping from the tranny than anywhere else I assumed the worst. Rear crank main or front tranny seal. I finally decided a couple of days ago that while I was doing an oil change I would jack the Z up higher and crawl under there and with a fine toothed comb, so to speak, try to locate the source. Still I couldn't find it. I just laid there, probably not the only that has done that, looking around and saying "I'm not coming out from under this car until I find something". I picked up my simple green and a rag and started wiping things down. When I got to the oil pan I noticed the bolts were pretty gunked up, most of them. I grabbed a flat head screwdriver and started scraping away at the mess. Then I would wipe it down with a rag. That's when it happened. I noticed that particular pan bolt moved! It wasn't even finger tight. First thing I checked for was a broken bolt but it was fine. I checked the others and all but the 4 at the front of the pan were loose! Not as loose as the first one though it took 3/4 to a full turn to snug them all up. After that I cleaned everything up and have put over 200 miles on it and no more leaks, yet. I still, when I think about it, can't believe they were that loose. I can't figure out why. Maybe someone has experienced this?

 Yup. I experienced the loose pan bolts multiple times on my first Z. I just got in the habit of checking them when I was under the car.

Yeah, definitely going to check those every time I do the oil change.