Want to use the factory trans lines into a trans cooler, without cutting the lines. Does anyone make a GM quick disconnect to barb fitting, or an adapter for the threaded end to a barb?

 

I'm not sure what the thread pitch is, but your local parts store should have a brass fitting that will thread into your radiator with a 3/8 nipple on it. I just installed my cooler the other day, and the kit didn't come with the right size fitting. Luckily, I had some in a bin, and one happened to be the right size.