Same way you got so good at running heavy equipment... Just done a lot with them. As much as some dog on Autozone workers, I learned a lot while working there too. Not from AZ though, but either from customers, or customer questions that made me look it up... Otherwise, just been working on vehicles in general a lot over the years. Started at 14 or so on vehicles, earlier on diesels. Farm life will do that to you...Geeze-o-pete Roger, how did you get so smart about things at such a young age?.... Happy Birthday!