A little food for thought. My truck sat, for the most part, for 4 years total. I started it, and drove.it every 3-4 months, maybe 10-15 miles. In that time, about the first 2 years, the seals in the transmission must have shrunk. When idling, the transmission would leak to the point of a steady drip. After driving a little, it stopped. I was told the transmission would need to be yanked, and seals replaced. This would cost quite a bit. Being the frugal guy I am, I put in a Bottle of ATF seal fix, to treat the seals. Gradually, over a few months, and more frequent driving, the transmission stopped leaking. Now, I drive it daily, and there has not been any leaks, for at least a year. The stop leak stuff was put in, about two years ago, and I have had zero issues. Zero. The transmission has about 189,000 mile on it, and never rebuilt.