MECHANISM: slider acts like rigid body when upper limit is reached

Hello everybody!
I'm using Creo 7 to simulate a mechanism that uses a piston (slider constraint with lower and upper limit, the green part) to partially rotate a cranck mechanism . The problem is that the rotating part wants to pull the piston beyond its limits and then simulation crashes. Actually when the piston is fully extended it acts as a rigid body, What I'd like to do is:
- Extend the piston
- Start rotating the levers
- Stop rotating
- Retract the piston
Any suggestion? I thought to replace the piston with a single part (a rod) but as simulation is not "correct"

Any suggestion?

Best regards
Stefano