Transmission cooling line fitting size help

I have put transmission coolers on about every car I have owned for the past 30-40 years. I always use the hose and fittings that come with them. It has worked great. Just like anything you do, got to do a good job. Make sure hoses are on deep on the tubes and fittings and clamps are tight. Probably not the most professional looking job if you are a 99% type guy, but functional.

Back in my youth when I was a poor boy in the hood, I used fuel line. Didn’t know there was such a thing a transmission line. Wouldn’t have bought it anyway if I had free fuel line lying around. Poor people have poor ways. Come to think of it, never saw a piece of gas welding rod till I was in my 20s. Thought everybody used coat hangers.

Moral of my story: If you want a top quality job, it costs time and money. If you just need functional, that is cheaper and easier, but if you are a cheapskate hillbilly, you can make about anything work......