I have a pit and a german shepherd and for the most part they are great. They do rough house some times and it is usually playful. Some times though they do get a little carried away and have to be broken up. After we calm them down and they have both been corrected it is usually fine. Do they usually play? If they do I would keep an eye on them and see who is causing the issue. My parents have a pit as well as two labs and a lot of the time they gang up on her because she is a puppy and new to the house hold. They will play keep away with all of the toys and if she tries to go for something the labs will snap at her and she thinks that means play time, which usually turns into a fight. Some times playful and sometimes not. So, just keep an eye out and see if its playful or viscous. Also if you haven’t already I would look into obedience classes for both of them to take together. That way they can be monitered by a professional. Hope this helps.