SHEET AS 1775992 - Caterpillar

The hydraulic control valve may become overheated if the bucket is operated continuously under relief conditions.
To warm up the hydraulic oil, push down the throttle until a medium engine speed is achieved. Run the engine for approximately five minutes and move the bucket control lever intermittently from the Bucket Dump position to the HOLD position. Keep the bucket control lever in the HOLD position for 10 to 15 seconds. Return the bucket control lever to the HOLD position for five to ten seconds.
Push the throttle pedal to the maximum engine speed and repeat Step 2.This allows the oil to attain relief pressure, which causes the oil to warm up more rapidly.
Cycle all controls in order to circulate warm oil through all hydraulic cylinders and through all hydraulic lines.