>>>> he will run away with the ball when we are trying to get it.
FWIW, My dog did -- and still does -- this. She's not guarding the ball. She's just not interested in the ball, or any other retrieval object, very much at all. What she loves are games of chase and touch (remember "Calvinball" from Calvin and Hobbes? That's Annie's favorite), and the ball is just a way for her to get this started.
And sometimes, clearly, she's bored with ball games and just takes the ball out of circulation. On walks, when I've thrown a stick to the point of boredom for her, she goes through the most amazing and creative contortions not to retrieve it to me, although she clearly understands what I'm asking. If I insist she'll bring it to me, but I anymore I cut the game off at a good retrieve before we get to that point.
I've never pushed her hard on retrieving -- it's not that important to me, and we do lots of other things together (walks, games of tag, training games) that I prefer, too. I did do basic retrieve to hand work with her, starting off with exchanging the ball for treats. She does this nicely for short periods of time, but she obviously thinks of it has a "have to" not a "love to".
She's very loving, responsive, and well behaved and enjoys all kinds of training exercises -- it's not a dominance issue for her.
My first GSD loved the ball with a purple passion from the time she could stagger and would retrieve until she dropped.