Automatic transmission - a wonderful invention of mankind! It saves the driver from having to juggle with three pedals, it itself regulates the fluctuations in torque and shifts gears.
Automatic transmission
The most common and reliable are hydromechanical "machines". They were invented in the USA in the early 30s. The main components of the box:
- planetary gears;
- valve body;
- torque converter (clutch).
Not everyone goes into details - what happens when the accelerator or brake pedal is pressed. The driver is guided by the dashboard:
- In the neutral position of the automatic transmission selector, the "N" indicator lights up.
- Reverse is on, “R” is on.
- Move forward - "D".
Selector sensor
In order for the car to understand what the driver wants from him, an automatic transmission selector position sensor is installed in the box. It transfers data to the box controller, is responsible for turning on the reverse signals and controls the starter drive. As a rule, it is located on the shaft of the automatic transmission lever.
A faulty automatic transmission selector sensor leads to incorrect operation of the box (it includes emergency mode) or the car does not move at all.
If the "HOLD" indicator on the dashboard lights up, the sensor is defective. Common causes:
- Contact wires are erased. The sensor wiring is too close to the automatic transmission selector. Constant switching of modes deform already thin wires.
- After removing the box, the sensor contact was connected poorly or not connected at all (forgot, and this happens).
- No crankcase protection - no sensor protection from dirt and water. It is enough to drive through a small puddle so that the water gets into the contacts.
What caused the malfunction in a particular case, computer diagnostics and visual inspection will tell.
Automatic selector
The gear lever is a unique way of communication between the driver and the car. With each new car model, it is being improved more and more, and in addition to the main handle, it is slowly overgrown with buttons for additional features and indicators.
The location of the lever differs depending on the model of the machine. In modern cars, the steering column is also common in the center of the dashboard (if the driver's landing is high, then on the console).
To prevent accidental switching between modes, a button is provided on the selector. It is located on the side, top or front. While it is not pressed, you cannot change the range of the lever. A stepped slot for moving the selector also prevents unnecessary range switching.
In the steering column version, the lever can be moved after the driver pulls it towards himself.
Selector Repair
Incorrect operation of the gearbox can be caused not only by a problem with the sensor, but also by malfunctions in the selector system. For example, thickening of the grease leads to the fact that on a frosty morning it is difficult to start the car or switching ranges is accompanied by jerks and jerks.
Incorrect switching modes (often happens with drivers who are used to a manual gearbox), aggressive driving style, reverse gear or parking until the car stops completely - all this affects the operation of the selector and disables it.
How to clean the selector yourself
Before surrendering to the mechanics of service stations, you can inspect the unit in a garage.
Dismantling:
- Before removing the selector, be sure to mark with paint the location of the parts in relation to the box unit and the movable part of the selector.
- We remove the battery tray, the air filter housing and, if available, the cruise control vacuum pump (we unscrew the 8 "bolt and remove the mustache from the groove).
- We snap off the gearshift cable from the washer and axle, then remove it, but it is better to do this together with the traction.
- Without making any effort, we unscrew and remove the 13 "nut from the splines of the shaft. We'll have to sway it a bit and pry it off (but very carefully).
- Since there are many connection wires, you can clean the selector without disconnecting them completely, that is, in place. We remove the connector with the main harness (we unscrew two bolts of 12 "). You can remove the other two by completely disconnecting the selector, but you must take into account the condition of the wires and the ability to get to the connector (one of them is connected under the box).
- Remove the wire cover (it is held on two screws), slightly prying it with a screwdriver.
- We disassemble the selector itself - unscrew the 4 screws. We reveal it.
- The main thing is not to lose 3 contact crackers and 3 springs (one of them is double).
- We wash off the old grease with gasoline. The selector contacts are well cleaned with kerosene and WD40. If the dirt is not washable, you can use fine polishing sandpaper and an ink eraser.
- Apply silicone grease.
- We collect everything in reverse order, not forgetting to combine the labels.
After this procedure, the selector should again work in normal mode.
Replacing the selector lever
After cleaning, the opposite situation may occur - the box will continue to junk. If the malfunction indicator still lights up on the dashboard, you will have to go to a car service and trust the professionals. Using computer diagnostics, a mechanic will identify and, if possible, eliminate errors.
Replacing the selector is a last resort. They resort to it when repair is impossible or there are no spare parts for replacement. For example, with a mechanical breakdown of the lever, its mounting base (the pin is metal, but if desired, it can be bent or broken).
For older cars, there is a used selector. Buying a new one, installing and configuring it will cost the car owner quite expensive.
Conclusion
The automatic transmission selector is a pretty fragile thing. Timely oil change and diagnostics, careful switching of modes, the presence of protection and a casing will help to avoid unnecessary financial costs. Good luck