2004 Ford Explorer ABS light on 4X4 blinks

Abs light on 4x4 blinks then goes off has automatic 4x4. While driving abs light on 4x4 hi light comes on then vehicle jerks as if going inot 4x4 hi on dry pavement. Makes a clank sound and releases. Last week vehicle did same thing and car died got vehicle started but could on drive max 30mph. Abs light on and intermittent 4x4 hi light on off flashing