What are the symptoms of a broken transmission oil pump?
3 Answers
The symptoms of a broken transmission oil pump include: oil leakage, jerking, vibration, noise, water ingress, insufficient power, failure to start, weak starting, gear shifting impact, high fuel consumption, inability of the oil pump to generate pressure, slipping phenomena, etc. A broken oil pump can produce excessive iron powder, leading to blockage of the oil circuit plate. It is recommended that car owners address the issue promptly. The transmission has two oil pumps installed in one assembly, separated by a partition, working at the same speed as the engine. The main oil pump supplies oil to the entire system, while the return oil pump is only responsible for pumping the oil from the torque converter oil pan back to the transmission oil pan, without requiring pressure. The main oil pump has two oil circuits: one for lubrication, supplying oil to the friction plates and clutch plates of each gear in the transmission; the other for gear shifting, and it also helps to reduce oil temperature, mainly supplying the pressure regulation device.
Recently when driving my buddy's old car, I noticed something was off. The most obvious symptom of a failing transmission oil pump is difficulty shifting gears, especially at low speeds where it feels like being dragged. There's constant mechanical rattling noise inside the car, as if metal shavings were churning, and even flooring the accelerator results in sluggish acceleration with no power. The oil temperature gauge frequently spikes near the red line while the cooling fan roars nonstop. Last week at the repair shop, the mechanic said insufficient oil pressure could cause clutch slippage and potentially total transmission failure. If you see the yellow gear-shaped warning light on the dashboard, don't push it - pull over immediately and call for assistance. Repairs could cost anywhere from several thousand yuan, with delays potentially running the bill over ten thousand.
Last time on the highway, I suddenly heard a metal scraping sound from the transmission area, which scared me into slowing down immediately. The most notable characteristic of oil pump failure is that the abnormal noise becomes more pronounced as the RPM increases, sounding like sandpaper grinding against bearings when accelerating. The car also shakes violently twice when shifting into reverse, clearly indicating abnormal hydraulic pressure due to insufficient force. A friend reminded me to check the transmission fluid color—healthy fluid is wine-red, but turns black and murky with metal particles mixed in when the oil pump fails. I later learned that such failures must be repaired promptly, or the entire valve body will wear out. It's recommended to change the transmission fluid every 60,000 kilometers to significantly reduce the risk of pump failure.
