When you drive your car, you’re using the transmission or “trans” as the word refers to it. It’s working off of shifting into overdrive!
However, not all transmissions are the same. Some are in automatic mode when you press the shift button, while others are in manual mode when you press the knob.
The one and only time your transmission should be in overdrive is when heavy acceleration is needed and more power is needed. This occurs when temperatures rise on a vehicle and heat necessary for an engine to work is generated.
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Check the brake light switch
If your car has a break light, make sure it is working. If a brake light is illuminated when the ignition is turned on, the car has an automatic transmission that detects a change in speed and turns on the brake light.
If a break light is not illuminated when the car starts, then it may be time to replace the transmission. A properly functioning transmission will smoothly shift into park or drive without stopping or resorts to shifting into park or drive.
If your vehicle has a break light that does not turn on when the ignition is turned on, check to see if it needs replacing. If it does not need replacing, then there may be a problem with the automatic transmission which will cause one part to shift into place before another takes its place and shifts into park or drive.
Try taking your vehicle to an auto repair shop for service to see if they can fix the problem.
Check the throttle position sensor
When your transmission is in overdrive, your car will shift into the higher gear more often. However, if your car does not have an overdrive shift, then you can check the throttle position sensor.
This sensor is located near the transmission case and monitors engine speed at the throttle pedal. When the pedal is pressed down, it monitors more pressure than before.
When engine speed is present, the sensor monitors when a piston on the transmission case moves up and down. If this piston does not move up or down at a consistent rate, then the sensor fails and your automatic needs to be replaced.
You can check your throttle position sensors by removing both legs of the shifter and pulling off the cable housing. Then you can physically check whether or not they are working by pressing where it feels like a piston would move. If it does not seem to work then you need to replace it.
Replace the transmission filter
If your car has an automatic transmission, you should pay close attention to the filter. This can be a little complicated, so keep reading!
An automatic transmission has two gears inside it. The first is a flywheel that shifts from one side of the engine to the other via a gearbox. The second is the transmission itself, which goes into one or more rear wheels and moves them forward or back with a wheelbase.
The flywheel needs to be removed and cleaned when it needs to be replaced. This can be done by using a Jack or another strong tool, removing and replacing the flywheel, and reusing the old one if done properly.
Replace the filter when it becomes necessary (when somebody changes oil or washcloth,) otherwise it can create some confusion when trying to shift into second or overdrive.
Flush the transmission and replace the fluid
If your car has a manual transmission, you can assume that it will not shift into overdrive mode when you drive. This is because the automatic transmission was designed to serve as an emergency shift feature for drivers.
If your car has a traditional clutch, then it is possible to manually shift into overdrive mode. The trouble with this method is that you need to be able to do so at a moments notice.
With the assist pedal on your foot, you can transition from first to second and back again in what is called Manual Overdrive mode. However, in order for this to work, you must have the right sized battery and be in a position to pull the move quickly.
Have the codes read and check fluid levels
If your car does not shift into overdrive or into any other mode automatically, you can determine if it needs to by looking at the fluid levels.
If the transmission is using too much oil or diesel fuel, it will show as a low or high fluid level. A vehicle with an automatic transmission that requires additional fuel must have more oil and/or diesel in order for the transmission to work.
If your car does not shift into overdrive automatically, you can check the oil and/or add enough of the correct oil and/or use a synthetic oil.
Have a manual shift override kit installed
If your automatic transmission has a manual shift override kit, you should install it. This is a cheap and easy upgrade to have.
When the car is in park or stop, a small lever on the transmission located on the rear end engages a series of gears inside to shift into overdrive. When driving in forward or drive speeds, the shifting action moves the control knob on top of the transmissions rear end which in turn shifts into overdrive.
By moving the control knob and/or shifting knob action, you can easily create two different setups for your automatic transmission. The easiest is to buy an inexpensive plastic kit that fits onto the front of the transmission and around the shifter, thus creating a static hold that shifts into overdrive when in park or shut. The second is to buy a ELECTRONIC OVERRIDE KIT!
This one is more expensive but saves you from having to manually engage and disengage each gearshift when parking or turning around in traffic.
Adjust the throttle position sensor linkage
When your car is in overdrive, the transmission will move the shift knob up to shift into overdrive. However, if you have the car in manual mode, then the transmission won’t do this.
This is due to a faulty throttle position sensor (TPS). When your car is in manual mode, and shifts into overdrive, the TPS detects that it is moving and shifts into a higher gear.
When you press the gas or turn the wheel, it sends a signal to the car that you want to drive. However, if there is an issue with the TPS, then it won’t shift out of overdrive. Instead, it will remain in first gear which may be difficult to find without using a handheld device.
If you have this problem, then look for an open spot between first and second gears. It should have some pressure on it while driving.
Replace the TPS sensor
If your car has an automatic transmission, you should change the transmission stress sensor (TPS) sensor. The TPS Sensor moves when the engine is shifting and Overdrive or Drive mode. This moves the transmisison switch to Transmision mode which forces the transmission to shift into overdrive or drive mode.
When this happens, it can remove some of the smooth, seamless shifting that you are used to with an automatic. With a manual transmission, if you push your car into a corner hard, there will be more resistance and your car will hold its straightness for a second before turning slightly until it shifts into forward or back motion.
With an automatic, you do not lose this feel because of the TPS sensor. There are two types of TPS sensors. The one mentioned above that moves the transmisson switch, has a spring in it to keep it in place. The other type does not have this feature and needs a shaft to move.