Factors to check: 1. Is the power output device normal? 2. Is the oil pump damaged? 3. Is there a failure of the up and down vehicle shift valves? 4. Is there a failure of the system multi-way valve main relief valve? Solutions: 1. Check if the take-up clutch has output and engage the take-up clutch. 2. Confirm the rotation direction of the oil pump and replace the oil pump. 3. Confirm that the shift valves have turned to the proper position. 4. Check if the main relief valve is stuck or damaged and clean or replace the main relief valve.