Fault Phenomenon: SANY SW956 wheel loader transmission oil pressure unstable, with cavitation noise, shift shock.

Troubleshooting Process:
– Checked suction line: transmission variable pump suction line fitting loose or hose aged and cracked.
– Checked oil level: transmission fluid level too low.
– Checked seal: pump inlet seal aged.
– Checked oil quality: foamy fluid.

Root Cause: The transmission variable pump suction line fitting is loose, allowing air to be drawn into the pump, causing oil pressure fluctuations and cavitation.

Required Parts: Tighten or replace suction line, replace seals.