The gearbox is an integral part of the vehicle's transmission. It operates in a constant load mode, transmitting torque from the engine to the axle shafts or propeller shaft. The checkpoint is a complex mechanism that requires timely maintenance and repair. Over time, the transmission wears out, individual units and parts fail, which is detailed below.
What is an automotive transmission?
The transmission is a bunch of complex components and assemblies that transmit and distribute torque to the drive wheels from the engine. The transmission plays a key role in the transmission. If the gearbox fails, the car may stop driving in any gear, or even stop driving.
The gearbox consists of a rocker, which, through forks, moves the gear blocks, changing gears.
Signs of a faulty transmission
You can find out about a malfunction of the gearbox by the following signs:
- gear shifting with difficulty
- inability to downshift the first time
- transmission shuts itself off
- increased noise (characteristic howl) when accelerating;
- oil is leaking from under the transmission.
The above signs require immediate intervention, otherwise there is a risk of failure of the entire unit.
The main malfunctions of the manual transmission and their causes
List of common faults:
The transmission is not included. There are several reasons for this:
- insufficient oil level;
- transmission oil has lost its properties, does not minimize friction and does not remove enough heat;
- the rocker or gear cable is worn out (the rocker is loose, the cable is stretched);
- the amount of synchronizer
Increased operating noise. The reasons:
- wear of the bearing of the primary or secondary shaft;
- wear on the teeth of the gear block;
- insufficient adhesion between the gears.
Knocks out the transmission. Usually knocks out 2nd and 3rd gear, it is they who are often used by drivers in city mode. The reasons:
- wear of synchronizers;
- wear of synchronizer couplings;
- failure of the gear selection mechanism or backstage.
The gear is difficult to turn on (you need to look for the necessary gear):
- wear of the stage.
Leaks and low levels of operating fluids
The manual transmission has a minimum of 2 oil seals - for the input shaft and the secondary, or for the axle shafts. Also, the body can consist of two parts, as well as a pallet, which is sealed with a sealant or gasket. During gearbox operation, the oil seals fail due to vibrations of the shafts, which in turn vibrate from bearing wear. Natural aging (the oil seal becomes tanned) is also one of the reasons why oil leaks.
Often, oil flows from under the sump, the reason for this may be the uneven plane of the gearbox pan, wear of the gasket and sealant. Depending on the severity of the problem, the oil can take years or several years. Since in many manual transmissions the oil level barely exceeds 2 liters, the loss of 300-500 grams will significantly affect the resource of rubbing components. If the gearbox provides a dipstick, this will facilitate the control process.
The problem with solenoids occurs on robotic and automatic transmissions. The solenoid serves to control the flow of transmission oil, that is, it controls the gearbox operating mode. If there is a lack of transmission oil, in this case ATF, the solenoids begin to work incorrectly, provoking an untimely gear change. From here, the transition to the top gear is accompanied by sharp jerks and slippages, and this is an early wear of the clutch pack and oil contamination.
The most common cause of gearbox problems is the clutch. A conventional clutch consists of a basket, driven disc and release bearing. The release bearing is pressed by a fork, which is pressed by the engine through a cable or a hydraulic cylinder. The clutch decouples the gearbox and the internal combustion engine to enable gear shifting. Clutch malfunctions that make it difficult or impossible to shift:
- wear of the driven disc, which means the distance between the flywheel and the basket is minimal, the gear will change with a grinding noise;
- breakage of the release bearing
- leaking clutch master or slave cylinder
- stretching the clutch cable.
The main indicator that the clutch package needs to be replaced is that the car starts off at 1500 rpm and above.
In an automatic transmission, the clutch is played by a torque converter, which consists of a clutch package. The gas turbine engine is lubricated with oil, but sharp accelerations, slipping, insufficient oil and its contamination shortens the resource of the “donut”, while the gear shift in an automatic transmission deteriorates.
Worn needle bearings
The gears on the output shaft of the manual transmission are mounted on needle bearings. They serve to ensure the alignment of shafts and gears. On this bearing, the gear rotates without transmitting torque. Needle bearings solve two problems: they simplify the design of the gearbox and provide axial movement of the clutch to engage the gear.
Recommendations for the operation and maintenance of manual transmission
- The oil level must always comply with the factory recommendations. The main thing is not to overflow the oil, otherwise it will be squeezed out through the oil seals.
- Even if the manufacturer reports that there is enough oil in the gearbox for the entire service life. If you follow these recommendations, your transmission will immediately fail. For manual transmissions, the oil change interval is 80-100 thousand km, for automatic transmissions from 30 to 70 thousand km.
- Change the clutch in time, otherwise insufficient squeezing will provoke early wear of the synchronizers.
- At the slightest manifestations of a gearbox malfunction, contact a car service in a timely manner.
- Pay attention to the gearbox mountings, when worn, the transmission will "dangle", and the gears will be tightly engaged and disengaged spontaneously.
- Timely diagnostics is the key to the durability of the unit.
- A moderate style of driving without slipping will allow the checkpoint to last for the prescribed period.
- Only engage and disengage gears with the clutch depressed.