An Automatic Transmission is a type of motor transmission fitted in vehicles. It automatically changes the vehicle’s gear ratio as it moves. Thus, the driver does not require to shift gears. Instead of using the clutch this type of transmission uses the torque converter. This fluid coupling uses a separate pump and a turbine spinning in opposite directions in the converter. This allows the engine to spin freely from the transmission.
What is a Shift Linkage?
The shift linkage is situated in the transmission tunnel of the automobile. And except for the shift knob – it is accessible from underneath the car. As the linkage is situated above the transmission there is little space to reach the upper retaining pin. This linkage turns the gears by shifting them to the desired position. The gears may be shifted into neutral, 1st, 2nd, 3rd, park, drive, and overdrive. These gears depend upon the model of the automobile.
Why do you adjust the Shift Linkage on an Automatic Transmission?
The automatic transmission linkage requires to be aligned with the transmission for the gear shift to change gears correctly. When the gear shift does not shift gears correctly or move them to the correct position then the shift linkage requires to be adjusted. This adjustment should align the linkage to the corresponding gear.
How to Adjust the Shift Linkage on an Automatic Transmission?
If you hear buzzing, humming, or whining from the car or if there is a delayed response from the car transmission. It is time to look at the shift linkage of your vehicle. It is prudent to identify the issues right away and remedy them or they will harm the transmission. Here is how you correct the shift linkage on the automatic transmission. This information applies to cars produces between 1985 – 95. These models have an automatic shift linkage, mechanical shift linkage, and lever assembly.
What is a Shift Linkage Bushing?
For your car to run smoothly you need to keep the shift linkage and its associated components in an optimal condition. It should shift smoothly and efficiently each and every time. Each time you service the transmission check the shift linkage bushing too. This bushing is designed to protect the linkage components and offers a bearing surface to some of the moving parts. If it is worn out or damaged it needs to be replaced with a new one to correct and support the shifters function.
Tools you will need: Screwdriver, jack stands, wrenches, nuts, and bolts.
Method: All automatic transmissions have a similar shift linkage. The shift linkage between the transmission and the cabin may differ in different models but their function is the same. There is a column shift and a floor shift – they both are operated by cables. Transmission issues are resolved by adjusting the shift linkage. Here are the steps to correct it.
Step 1 – Length adjustment
The first step is to adjust the length of the shift linkage. Place the transmission into neutral. Use the adjustment nuts in the middle of the shift tube to set the transmission into neutral. While the nut is loose turn the screw to get the right length. You turn the adjustment threads in or out to achieve this.
The shift tube should be attuned. It is essential to get the shift socket right in the middle of the mounting hole while the shift tube is connected to the transaxle shaft by a tightened set bolt. Adjust the length correctly and do not tighten the jam nut on the shift tube.
Next, install the cockpit shifter mechanism. Then bolt the shifter’s base to the slope through the mounting holes in the stick shift’s base. This helps the chassis’ shifter mount the adjustment bolts in the center. This in turn helps to finetune – from front to the back.
After the shifter base is installed and tightened, you will require to adjust and alter the shift tube locking. This is a tricky procedure and requires a practiced hand. Now find the first gear and tighten the shift tube adjustment nut temporarily – that is – if you think it is still loose.
Next, use the stick shift to place your car in gear. You will be in the 1st or 3rd gear of you have not locked your shift tube. To get the 1st gear you will require to loosen and tighten the shift shaft adjustment nut. Move the shift tube locking to get the 1st gear.
Step 2 – Shift Shaft Locking
After placing the transaxle in the 1st gear finetune the shift shaft locking, you will do the final adjustments. This fine-tuning prepares the shifter to move smoothly and precisely while shifting gears. You will attain an accurate adjustment by trial and error and another helping hand.
First, loosen the shift shaft adjustment nut when the transaxle is in the 1st gear. Push the stick shift lever forward and then to the left. Hold it firmly in the 1st gear. You could ask your helper to hold it in position.
While the shifter is in 1st gear, tighten the shift tube nuts using two wrenches. One wrench is meant to hold the back end of the shift shaft in position while the other wrench helps tighten the jam nut at the front end. Ensure you do not torque the shift tube while tightening the nut or it will affect the rear tube.
Step 3 – Check the Gears
After you have completed the above steps – try the gears. You should be able to find all of them. While looking for the gears do not force the shifter. You will be able to find them easily when the clutch is pushed in.
If you find all the gears when the engine is switched off – try to test the reverse. Some shifters have a reverse lockout to prevent accidental reverse shifts. Now pull the reverse lockout and place the transmission in reverse – to test it. If you are in reverse then you are fine.
Now test drive the car to check if you can find all the gears. If you cannot find all the gears then you need to repeat the above-mentioned procedure. As said before – this is achieved correctly by trial and error.
As very few people were able to get it right the first time you will need to be patient. But once you have got it – the process of adjusting the shift linkage is very easy.
A vehicle’s transmission requires the devices to match the ratio which in turn decides the power available to the driving conditions. One of the 4 functions of the power transmission is power matching. This system transmits power from the engine to the rear wheels beside it helps reduce the speed available to the rear wheels. It also helps alter the wheel speed to engine speed ratio to suit the road conditions. Lastly, it transmits power through the right-angle drive as the crankshaft and rear axle are usually are perpendicular to each other.
In manual gearboxes, changing gears is carried out by the driver. Depending on the level of automation the gearboxes may have electronic and actuator systems that take over this function completely or partially. But certain transmission functions like reverse, neutral and park are still controlled by the driver using the shifting device.
The shift linkage system comprises a transmission shifter cable and a shift handle. If there are problems with the transmission. Or if the above procedure has not been executed correctly you may hear humming, grinding, and whining. You may experience leakage issues, fluid problems, and leakage in the clutch. If you notice these problems, confirm that the shift linkage of your vehicle is working correctly. This will help you determine if you need a replacement or a simple adjustment. Do not forget to get the transmission shift cable bushing checked. If it is broken or worn get it replaced.