[fostermom]

I raised my children with goldens (your oh, so eager to please type dogs)...when I went to adopt a dog from a shelter a rotti who looked overwhelmed by the shelter scenario grabbed my heartstrings...and after having Reno, I could never go back to goldens!!! I AM hooked on rottweilers. But the basics of what both breeds need is the same...structure, training, consistency, and rewarding appropriate behavior (decide how you want the dog to behave in your home, show him CONSISTENTLY..and let him know when he gets it right).
The adolescent I fostered had quite a mind of his own...he was happy to comply with what you wanted, but he HAD to be shown in a way that made HIM decide that he really wanted to do it...the old school dog training concepts that I raised my goldens on didn't cut it with him...I learned an enormous amount from that dog (and of course the trainer who showed me the error of my ways)...each dog is different...one method of training doesn't work with every dog. This dog is telling you he's not happy with some of the things you're doing, but in the end complys....so maybe you need to start trying a different approach. Not messing with his food was mentioned numerous times here...not trying to pet him on top the head, not bending over him, etc was also mentioned.. the basics of Nothing in Life is Free (NILIF) training was mentioned..if you could tell us more specifics about what you were doing when he growled at you, perhaps other things could be suggested.
I am soooo glad I fostered Zach...I learned so much from him....and btw, his new family LOVES him....the wife is doing advanced obedience with him and Zach is getting perfect scores....rotti's are a working breed so have bred into them the capacity to make up their own minds about things (independent thinkers!)...you might get some with a lab type temperment (there are lots of rotti's that are loveable lugs out there) but there are some that have to be convinced it's THEIR idea to do things your way...like Zach!
Perhaps people on this board could suggest some good books which might help...and I would still urge you to take a few sessions with a trainer who can show you how to use positive reinforcement in working with this boy.
Again, best of luck.