As we all know, the quality of automatic transmission oil directly affects the service life of automatic transmission. Usually, when the automatic transmission fails, the inspection of the automatic transmission fluid is the first step! Because the quality of automatic transmission oil is an important basis to analyze the internal problems of automatic transmission.

正常情况下的自动变速箱油色泽光亮，流动均匀。如果自动变速箱油液的颜色、粘度有了变化，则表明自动变速箱油已经变质，此时就需要更换自动变速箱油，当自动变速箱油有了烧焦味或油液状态有大量粉末状物及乳状等，这时说明自动变速箱内部已经严重磨损。那么是什么原因会导致自动变速箱油变质呢?

Under normal circumstances, the automatic transmission oil is bright and flows evenly. If the color and viscosity of the automatic transmission oil have changed, it indicates that the automatic transmission oil has deteriorated. At this time, the automatic transmission oil needs to be replaced. When the automatic transmission oil has a burnt smell or a large amount of powder and emulsion in the oil state, it indicates that the internal of the automatic transmission has been seriously worn. So what causes the automatic transmission oil to deteriorate?

1、自动变速箱温度过高

1. Automatic transmission over temperature

自动变速箱运行时会因为内部元件运动摩擦而产生大量的热量，高温会破坏ATF的质量和摩擦特性，加剧内部元件磨损，ATF会变成褐色或暗红色并发出烧焦的味道，同时油泥/杂质等也会在变速箱内部产生，长期不更换变速箱油，将导致油液变质。

When the automatic transmission is running, a lot of heat will be generated due to the friction of the internal components. High temperature will damage the quality and friction characteristics of the ATF, aggravate the wear of the internal components. The ATF will turn brown or dark red and give off the smell of burning. At the same time, sludge / impurities will also be generated inside the transmission. If the transmission oil is not replaced for a long time, the oil will deteriorate.

2、自动变速箱进水

2. Water in automatic transmission

变速箱进水后油液会出现乳状，一般进水情况有两种，种：发动机冷却液通过散热器进入自动变速箱;第二种：雨水或洗车水从自动变速箱透气孔进入。自动变速箱进水后，车辆故障并不会立即反映出来，因此车主要定期对变速箱油进行观察。

There are two kinds of water inflow: the first is that the engine coolant enters the automatic transmission through the radiator; the second is that rain or car washing water enters the automatic transmission through the vent. Automatic transmission water, the vehicle fault will not be immediately reflected, so the car mainly regularly observe the transmission oil.

3、油面高度差误大

3. The oil level difference is too large

自动变速箱油位的高低，也将影响自动变速箱油的品质，从而出现变速箱故障。油位过低，油泵将吸入空气，使油液与空气混合，这种情况变速箱油会产生大量的泡沫，油位过高，会使行星齿轮和其他旋转部分浸在变速箱中，发生搅动油液现象。

The level of automatic transmission oil will also affect the quality of automatic transmission oil, resulting in transmission failure. If the oil level is too low, the oil pump will inhale the air and mix the oil with the air. In this case, the transmission oil will produce a lot of bubbles. The excessive oil level will cause the planetary gear and other rotating parts to be immersed in the gearbox, causing the phenomenon of stirring oil.

4、摩擦片打滑

4. Friction plate slipping

变速箱内部离合器、制动器的摩擦元件打滑会引起变速箱油的变质，此时变速箱油液往往呈黑色，并伴有焦味。导致发动机转速很高，但车速上升缓慢的故障，换档也会受影响。

The friction elements of the clutch and brake in the transmission will cause the deterioration of the transmission oil. At this time, the transmission oil is often black with scorching smell. As a result, the engine speed is very high, but the speed rises slowly, the gear shift will also be affected.

5、金属零件磨损严重

5. Serious wear of metal parts

如果变速箱油液中存在大量的金属碎末，这主要是由于变速箱内的金属零件磨损严重，如变速箱内的中间轴、轴承、离合器钢片等。

If there are a lot of metal debris in the transmission oil, it is mainly due to the serious wear of metal parts in the transmission, such as the intermediate shaft, bearing, clutch steel plate, etc.

6、摩擦材料脱落

6. Friction material falling off

这种现象大多出现在自动变速箱进水后，未进行维修，而只是更换变速箱油后继续使用，造成的摩擦片脱落的现象。

This phenomenon mostly occurs in the automatic transmission after water, without maintenance, but only after changing the transmission oil to continue to use, resulting in the phenomenon of friction plate falling off.