Automatic Transmission Cable Adjustment: Details and Peculiarities

Despite numerous advantages, automatic transmissions frequently become one of the most expensive assemblies for maintenance and repair. Automatic transmission failures frequently manifest themselves in kicks and jerks when shifting gears (car with automatic transmission starts to consume more fuel).

There may be many reasons for the abovementioned symptoms, but a specific reference should be made to the automatic transmission shift cable. In this article, we will consider the process of transmission adjustment, or, to be more precise, transmission cable adjustment and its peculiarities.

Automatic transmission cable: How to adjust and test this element

In the process of transmission operation, the shift cable gets stretched. However, the cable adjustment on different cars is performed taking into account a number of peculiarities. Some auto owners adjust the transmission cable in accordance with their personal needs. Car owners with aggressive driving style need the automatic transmission cable to be tensed. If you drive steadily, then the cable should be slightly loosened. Ideally, it is necessary to find an optimal balance. If the cable is adjusted correctly, the automatic transmission will operate more smoothly.

However, you should bear in mind the fact that the automatic transmission is adjusted not only by tensing or loosening the cable. Simultaneously with the shift cable adjustment, it is necessary to adjust the throttle cable, throttle valve, etc. Frequently, the adjustment process also includes the idle speed control valve.

The transmission cable design includes the following: cover, metal lug boss, adjustment nuts.

Let’s pay more attention to the transmission cable adjustment itself:

• Before starting any adjustment procedures, it is necessary to warm up the engine and the automatic transmission itself, so take a short ride (10-15 km) and stop, then the engine cooling fan must switch on at least 2 times at idle speed;
• The next step is to inspect holders of the transmission cables. The cable must be fixed on the supporting bracket (located above the throttle control lever, on the supporting bracket to the left of the lever, as well as on the junction pipe).
• Then it is necessary to switch off the engine and press the gas pedal. The throttle lever must be shifted to the end position (no place for free movement should be left).
• Now you have to release the gas pedal, the lever will return to its initial position. If there is the lever free movement, then the cable should be adjusted with the help of locknuts located on the supporting bracket. If you move the cable on the bracket to the left – you tense the cable, if you move it to the right – you loosen the cable.
• At the initial stage of adjustment, the cable should be tensed slightly (0.5-1 nut screw). Then you should take a test drive and estimate the car behavior and operation of the automatic transmission.

Useful video on transmission cable adjustment

To check the automatic transmission performance after adjustment, you have to pay attention to how gears are upshifted and downshifted. If you slightly press the gas pedal and the gear shifting is performed with jolts, then the automatic transmission cable is too tense. In case when slippage or jerks occur in pairs, then the cable is too loose.

It is also necessary to check the transmission operation in the kick-down mode. Firstly, you need to accelerate up to 50-60 km/h, then release the gas pedal and press the pedal again as far as it will go. If there is some delay in transmission operation when the gas pedal is pressed and a smooth jerk occurs when the kick-down mode is engaged then the cable is loose. If there are no delays, but a sharp jerk takes place, then the cable is too tense.

It is also important to take into account that each driver presses the gas pedal differently (some drivers push the gas pedal sharply to the floor, others press it gradually). If drivers entrust the cable adjustment to professional technicians, it is necessary to take part in test drives, because technicians do not take into account the driving style of the car owner.

Useful Tips

Before starting any adjustments, you need to clearly understand what result you want to achieve by the transmission cable adjustment. If you want your transmission to shift more smoothly, the cable should be loosened (the cable is lengthened by unscrewing one adjusting nut and screwing the other one).

To make the gear shifting process more distinct, it is necessary to reduce the length of the automatic transmission cable. But it should be borne in mind that too loosened cable can lead to delays in the transmission operation, or when the cable is too tense you can experience jerks during gear shifting. For this reason it is necessary to change the length of the cable gradually (on average, no more than half a millimeter at a time), and then check the transmission in action. If you adjust the transmission cable independently, it may be helpful to read the car manual to do the job right.

There is a large number of cars equipped with different types of internal combustion engines and automatic transmissions, which operate using different algorithms. For this reason, if you don’t have sufficient experience in this procedure, then it’s better to visit a professional repair shop and rely on experienced technicians to do this job.