A construction site reported that a Liugong CLG856III loader had a 3-second delay when shifting from Neutral to Forward. The machine would lunge forward once it engaged, and the transmission made a "whining" noise.
The technician checked the "Transmission Oil Dipstick." The level was very low. He added oil, but the level dropped immediately. He found oil leaking from the "Torque Converter Housing Drain Hole." He removed the transmission and disassembled the torque converter. The "Input Shaft Bearing" was destroyed. The bearing balls had turned into metal powder.
The destroyed bearing allowed the "Pump Drive Hub" to wobble. This wobble damaged the "Transmission Pump Seal," causing the massive oil leak. The low oil level starved the "Forward Clutch Piston." The delay was caused by the time it took to fill the clutch housing with the remaining low oil. The "whining" noise was the pump running dry.
The repair involved replacing the torque converter input shaft, bearing, and pump seal. The transmission filter was replaced, and the system was flushed to remove the bearing debris. The oil was refilled to the correct level. The engagement time returned to under 1 second.
