TOYOTA LANDCRUISER TRANSFER CASE

My 4wd Light Came On, And I Checked It You Can Spin The Rear Drive Shaft And The Front On Moves Also. With The Hubs Unlocked It Is In 2wd...

I Have 170000 Miles It Is An All Wheel Drive My Differatial Is Locked In And Has Been For 20000 Miles How Do I Get It Out Of Lock

Is It Normal To Here A Grinding Sound When Shifting From Four Low Back Into Four High?