I had a dog I name Zsa Zsa who was a Jack-Chi breed. She was abandoned in an apartment complex in my town at the time by a local low-down breeder (they finally caught her). I think she was abandoned because she was "too big." Everyone wanted small "purse" dogs then.

She had that Jack RT aggression but eventually she bonded with my Stepdad's bigger dog, Brooklyn (an austrian shepard). Something about hanging with Brooklyn regularly calmed her aggression. She's in pup pup heaven now. I still miss her.