Hi there, first post, so please bear with me. I have a 2007 case 440ct. Approx 4000hrs. Pilot controls. The machine starts and runs fine, but when I push the park brake button to unlock the brake, the left side track starts spinning in reverse. It won’t stop until I put the brake on. Any suggestions? I am a capable mechanic, just not very familiar with hydraulic systems yet. Any help or insight would be appreciated.