Oil Pan Leaking

I noticed a small amount of oil leaking from the bottom of the 4.6L V8 Northstar Engine. It has always had Synthetic Oil, and it was changed every 2000 miles (Documented) The car had been sitting for about one month when I noticed the leak. I took it in to my mechanic, he put a dye in the crankcase, and I brought it back the next day for a look see, and was advised it would cost $3,000. To replace the oil pan gasket because the trans and engine would have to be dropped to do the job. Sounds very high to me, what do you think.