Improper shifting is a sign of car transmission problems. The solution might be simple or complex, but get it inspected to avoid expensive repairs.
If your car is not shifting properly, you could end up with very expensive transmission repairs. So, how do you know if your car isn’t shifting the way it should? Watch for these signs to avoid serious transmission trouble.
Warning light comes on: A warning light alone doesn’t necessarily mean that you have a shifting problem, but if you notice it along with any of the symptoms that follow, you should get it checked out.
Car is shifting hard: The car feels as if it’s reluctant to shift gears the way it usually does, or isn’t shifting smoothly. You might notice a clunking or thudding sound when the car shifts gears, or has difficulty reaching the proper speed.
Gear changes for no reason: If you’re driving a manual transmission in a certain gear, and the car suddenly changes gear with no action on your part, or if it suddenly slides into neutral in an automatic, you have a shifting problem. You might notice a whining sound or a change in the usual sound from your engine when this happens.
Fluid leak: If you’re having trouble shifting, it could be something as simple as a transmission fluid leak. Usually, transmission fluid shouldn’t leak, and if you see a puddle of fluid under your car, that can be a sign of a clogged filter or a loose plug. Transmission fluid is clear red, and has a slightly sweet smell.
Delayed engagement: Your car waits for a bit before going into drive and moving forward. You’ve pushed the clutch pedal down, brought it up to the point where the gears should engage and move your car forward, but there’s a pause before the vehicle moves. Even if you rev the engine, there’s still a delay.
Any indication that your car is not shifting properly should be dealt with immediately. You might have a simple issue that can be repaired inexpensively, but if you wait too long you could end up with serious transmission trouble and have to pay to repair or even replace your transmission. Be sure to contact a mechanic to check your transmission fluid and other parts of the transmission system as soon as you experience any shifting problems.
Car Care, Maintenance and Repairs Guide Blog. From AutoFactorNg.com (#1 Auto Parts and Products Retailer).
Showing posts with label transmission. Show all posts
Showing posts with label transmission. Show all posts
Thursday, 21 December 2017
Tuesday, 21 November 2017
5 Causes of Automatic Transmission Fluid Leaks
If there is a leak of red transmission fluid that occurs underneath your vehicle, this is never a good sign. It will form stains on your garage floor but more importantly, it will cost you lots of money in repairing the leak and replacing the fluid.
The Top 5 Causes of Automatic Transmission Fluid Leaks
Your transmission may leak because of minor issues or critical issues. Despite which kind of issue that it is, you should never let a leaky transmission wait. Get it checked right away. If you wait to get a simple repair done, the problem will get much worse and cost you more money to fix. Below are the 5 main causes of automatic transmission fluid leaks.
1) Oil Pan & Drain Plug
There will eventually be wear and tear of your transmission pan. If the pan gets a small puncture or there are loose drain plugs or bolts, then a leak can occur. While on the road driving, the pan of your transmission could get damaged from all the loose rocks and debris on the road. If a big rock or other object were to damage the pan, the transmission will lose fluid quickly. You will know right away when this is happening. On the other hand, a small hole or puncture will take longer for you to notice. If your drain plugs or bolts are not tightened enough, they could cause a leak too. You can do this after you change the fluid.
2) Fluid Line is Cracked
The fluid line of a transmission is constructed of either steel or aluminum. This line is extremely durable but if it gets damaged with debris or exposed to heat too often, then the line will break or crack in time.
3) Seals are Broken
An automatic transmission sustains hydraulic pressure by using lots of transmission seals. However, over time, these seals will crack and get worn out, especially when being exposed to heat often. If you get a transmission leak from this, there are many areas of the transmission to check. You could inspect the pan gasket, plug seals, sensors, shifter housing seal, input shaft seal, output shaft seal, tail housing seal, and speedometer input seal.
4) Torque Converter Leakage
Transmission fluid is propelled into the whole system by the torque pump. If this torque pump has a crack anywhere on its body, it will leak transmission fluid.
5) Oil Pan Gasket Fails
Oil pan gaskets can be damaged or cracked due to poor manufacturing or constant exposure to hot temperatures. The oil pan gasket is cheap to replace so do it right away. Otherwise, more serious problems will occur.
The Method for Inspection
The auto mechanic will observe where the transmission fluid leak is coming from. They will be able to tell the location based on the dripping of this fluid. Most of the time, the transmission fluid will go down a path that has the least resistance to it. If the leak is caused by a part that is loose, this part will get tightened by the mechanic. If the part is damaged or cracked, then it will be replaced. Before any of this work is done though, the mechanic will give you an estimate on how much this will all cost to perform.
The Top 5 Causes of Automatic Transmission Fluid Leaks
Your transmission may leak because of minor issues or critical issues. Despite which kind of issue that it is, you should never let a leaky transmission wait. Get it checked right away. If you wait to get a simple repair done, the problem will get much worse and cost you more money to fix. Below are the 5 main causes of automatic transmission fluid leaks.
1) Oil Pan & Drain Plug
There will eventually be wear and tear of your transmission pan. If the pan gets a small puncture or there are loose drain plugs or bolts, then a leak can occur. While on the road driving, the pan of your transmission could get damaged from all the loose rocks and debris on the road. If a big rock or other object were to damage the pan, the transmission will lose fluid quickly. You will know right away when this is happening. On the other hand, a small hole or puncture will take longer for you to notice. If your drain plugs or bolts are not tightened enough, they could cause a leak too. You can do this after you change the fluid.
2) Fluid Line is Cracked
The fluid line of a transmission is constructed of either steel or aluminum. This line is extremely durable but if it gets damaged with debris or exposed to heat too often, then the line will break or crack in time.
3) Seals are Broken
An automatic transmission sustains hydraulic pressure by using lots of transmission seals. However, over time, these seals will crack and get worn out, especially when being exposed to heat often. If you get a transmission leak from this, there are many areas of the transmission to check. You could inspect the pan gasket, plug seals, sensors, shifter housing seal, input shaft seal, output shaft seal, tail housing seal, and speedometer input seal.
4) Torque Converter Leakage
Transmission fluid is propelled into the whole system by the torque pump. If this torque pump has a crack anywhere on its body, it will leak transmission fluid.
5) Oil Pan Gasket Fails
Oil pan gaskets can be damaged or cracked due to poor manufacturing or constant exposure to hot temperatures. The oil pan gasket is cheap to replace so do it right away. Otherwise, more serious problems will occur.
The Method for Inspection
The auto mechanic will observe where the transmission fluid leak is coming from. They will be able to tell the location based on the dripping of this fluid. Most of the time, the transmission fluid will go down a path that has the least resistance to it. If the leak is caused by a part that is loose, this part will get tightened by the mechanic. If the part is damaged or cracked, then it will be replaced. Before any of this work is done though, the mechanic will give you an estimate on how much this will all cost to perform.
Thursday, 13 July 2017
10 Most Common Transmission Problems
Determining what problem(s) your car has may seem like an impossible task, especially to the untrained eyes and ears of the average driver. It may be helpful to think of your car’s inner workings as similar to that of the human body.
For instance, if you have chest pain that could point toward any number of health issues, but if the chest pain exists in addition to difficulty breathing, then it is much more likely that asthma (or something very similar) is the cause. Automotive problems are diagnosed in a similar manner.
Problems that involve mechanical systems typically exhibit distinct sensations and sounds that act as indicators that a certain process isn’t working the way it is intended to. As soon as you recognize that something seems a bit “off” with your vehicle’s functionality, it is time to assess the issue and look for a way to fix it.
Diagnosing car problems yourself may seem like an impossible task, but try to think of it in terms of your own body. For instance, if your stomach begins to hurt without warning, you’ll probably start thinking of the last thing you ate in order to figure out why you are in pain. A similar type of thinking goes into diagnosing car trouble. The moment you start noticing something out of the ordinary, it’s time to start considering the problem and finding a way to fix it.
Automatic Transmission Cut AwayYour car’s transmission is a complex mechanical system that controls the application of power from the engine to the driveshaft. It experiences more wear and tear over time than most other parts of your vehicle due to the heat and friction produced by their many moving and interacting components.
Major issues are bound to arise if your transmission is not well maintained and/or symptoms of a problem are not checked by a professional soon after they develop.
Transmission repairs or replacements are inconvenient, stressful and typically quite expensive, so it’s a good idea to pay attention to any activity that seems unusual. Adhering to the recommended maintenance procedures and schedule intended to prevent problems will help your transmission last longer, perform better and require fewer repairs over its lifespan.
That said, if you’re having some car trouble, it is important to know what the most common types of transmission problems are so that you can easily diagnose them and get them fixed. Here is a list of 10 symptoms of transmission trouble and what signs you should look for.
Lack of Response
Ever notice that while driving that the car hesitates or refuses to go into gear? If you have, then there is definitely something wrong. The moment a driver shifts from park to drive the car should immediately go into the proper gear. For automatic transmissions, you might notice that when shifting into drive or park that there is a delay before you feel the gear engage. This is usually a transmission-based concern.
Manual transmissions can have the same lacking response issue, but after shifting into gear the engine’s RPMs will surge, but the car won’t move as fast as the engine sounds like it’s going. This is usually caused by a clutch that needs to be replaced, but may sometimes point to a more severe problem.
Whining, Clunking and Humming
It’s impossible to say exactly what your car will sound like when there is trouble with your transmission, but one thing is for sure, you’ll get a “I haven’t heard that sound before” feeling when you notice it. The sounds that are produced vary widely between different makes and models, but the best way to describe them is that you’ll probably hear a humming, buzzing or whining noise.
Manual transmissions will emit sounds that can be described as being slightly more mechanical, louder and abrupt sounding. A clunking sounds when you shift gears almost always lies within a transmission, while constant velocity joins or the differential may be the source if the clunking is coming from the underside of your car.
As mentioned already, it is always best to get the problem diagnosed and repaired as soon as possible and not wait until later when you “find the time” or “have the money”. If you wait until later what would have been a relatively inexpensive repair can easily become a much more costly one.
Leaking/Low Fluid
New Automatic Transmission FluidA leak is probably the most recognizable symptom and should be repaired as soon as possible. Letting the fluid leak is one of the most common causes transmission break down. Automatic transmission fluid (ATF) is the life-blood of a transmission as it lubricates, cleans and conditions the seals and acts as hydraulic fluid. Without it (or even if it gets too low), the engine will seize up and stop working completely.
ATF is bright red in color, clear and smells somewhat sweet if everything is working correctly. If this is what you find on your driveway, then all that needs to be fixed is the hole. If the fluid is dark and/or has a burnt smell then it’s time to get the fluid changed or flushed and repairs might be required.
To check if you’re running low on fluid, take your car for a short drive to warm it up and then lift the hood and read the dipstick (be sure the vehicle is on level ground). Unlike motor oil, transmission fluid is not burned off or consumed by a car so if the level is low then there is a leak somewhere that must be patched. It is recommended to top up the fluid anyway even if the leak still exists to make sure there is enough fluid for the transmission to function properly until you get it fixed.
To check the fluid level for a manual transmission, you must check at the transmission case (usually through the fill plug) – not with a dipstick under the hood.
Grinding or Shaking
A car is supposed to run smoothly and without any shaking, or jerking, and there is not supposed to be any grinding sounds. These all suggest that there is a problem with the gears. Manual transmissions commonly indicate problems by making a grinding noise or feeling when you shift into a gear. If the grinding occurs after engaging the clutch and shifting, this can be sign that the clutch may need to be replaced or adjusted. That said, it can also point towards several other issues including damaged or worn out gear synchronizes.
Automatic transmissions act a little differently. Instead of making a grinding noise, you will likely feel it take some time to wiggle into gear at first instead of the typical smooth transitions. As the problem gets worse, the transitions into the next gear become more jarring and involve more shaking. There are a few other reasons for grinding or shaking, but the appropriate course of action is still to have it inspected and serviced.
Burning Smell
Any burning smell coming from your car is a cause for concern. Overheating transmission fluid is one of the causes of a burning smell. Transmission fluid helps keep the parts lubricated and cooled so that they don’t get worn out and damaged.
If the fluid breaks down, the system runs too hot which it results in increased friction and corrosive activity as well as the build up of additional sludge and debris. If this is not taken care of, the transmission will eventually damage itself enough to break down completely. The end result is an expensive replacement. Common causes include low fluid level or using the incorrect brand/type of fluid. To check for these, see the instructions in the section on Low/Leaking Fluid above.
Refuses to Go Into Gear
If the car will not shift after engaging the clutch and trying to move the stick, take a look at the fluid to make sure that it is at the right level. Other causes include using the incorrect thickness (type) of fluid and the clutch linkage or shift cables needing adjustment. The source of the problem could also be the vehicle’s computer system.
If you’ve already inspected the fluid, you can try resetting it. To do this, detach the battery and let it stand for thirty minutes. Then, reattach and allow the system to reset itself. This usually takes around thirty minutes. If this doesn’t work either, then it’s time to take it to a mechanic.
Check Engine Light
Check Engine LightThe check engine light located on your car’s dashboard is a great early indicator that something is about to go wrong (or already has) with your car, and in particular with your transmission. While the light turns on for a number of reasons other than transmission issues, it very important not to ignore this helpful warning sign.
There are sensors placed in many areas of a car’s engine that alert the computer if it senses unusual activity coming from a particular process. The sensors on a transmission can pick up on the slightest jerks and vibrations than you are not able to see or feel.
Take the vehicle in and have it inspected. They can take look and immediately tell what is happening through the use of similar diagnostic tools and the car’s computer.
If you’d like to diagnose the problem yourself (and possibly save yourself a trip to the mechanic’s) you can buy a diagnostic scan tool that is plugged into the instrument panel on the driver’s side and return a code that corresponds to the part that needs attention. Whatever you do, do not assume that the check engine light can wait because it might be warning you of a serious problem in the near future.
Transmission Noisy in Neutral
Luckily, a transmission that is noisy (goes “bump”) when it is in neutral could have an inexpensive, simple solution such as adding some fluid or changing it. This could do the trick, as it does for several other issues on this list. If that doesn’t work, the transmission may require professional attention to replace worn out parts, most commonly the bearings, worn gear teeth or the reverse idler gear.
Gears Slipping
A transmission stays in a designated gear until a shift is performed by the driver (manual) or the computer (automatic). If the transmission is spontaneously slipping in an out of gear (or simply popping into neutral) while driving, I don’t need to tell you that this is a serious safety risk. When you need to step on the gas to avoid a dangerous situation, you need power delivered to the wheels, end of story. The cause can be the link that holds the gears is worn or broken. Get your car inspected and repaired as soon as possible.
Dragging Clutch
A dragging clutch describes the symptom experienced by manual transmissions that involves the clutch disk failing to disengage the flywheel when the clutch pedal is pressed. The clutch is still spinning with the engine which makes it anywhere from difficult to impossible to change gears. This difficulty is accompanied by a grinding noise each time you try to change gears.
Fortunately, this problem is considerably less expensive to repair than many other issues. More often than not, the cause of this is too much slack in the clutch pedal. With too much slack available, the linkage between the clutch disk and pedal can’t pull the clutch disk away from the flywheel.
Conclusion
It is important to keep up a regular maintenance schedule for your car. Many times major expensive repairs can be avoided if the vehicle is properly maintained. This is especially true if you notice something unusual. The car should be taken in immediately for service.
Brushing up on your knowledge of transmissions (at least the basics) is highly recommended as it can help you save money by avoiding costly inspections and doing simple procedures such as changing transmission fluid yourself as well as making you knowledgeable enough to avoid being over-repaired, over charged or simply ripped off.
For instance, if you have chest pain that could point toward any number of health issues, but if the chest pain exists in addition to difficulty breathing, then it is much more likely that asthma (or something very similar) is the cause. Automotive problems are diagnosed in a similar manner.
Problems that involve mechanical systems typically exhibit distinct sensations and sounds that act as indicators that a certain process isn’t working the way it is intended to. As soon as you recognize that something seems a bit “off” with your vehicle’s functionality, it is time to assess the issue and look for a way to fix it.
Diagnosing car problems yourself may seem like an impossible task, but try to think of it in terms of your own body. For instance, if your stomach begins to hurt without warning, you’ll probably start thinking of the last thing you ate in order to figure out why you are in pain. A similar type of thinking goes into diagnosing car trouble. The moment you start noticing something out of the ordinary, it’s time to start considering the problem and finding a way to fix it.
Automatic Transmission Cut AwayYour car’s transmission is a complex mechanical system that controls the application of power from the engine to the driveshaft. It experiences more wear and tear over time than most other parts of your vehicle due to the heat and friction produced by their many moving and interacting components.
Major issues are bound to arise if your transmission is not well maintained and/or symptoms of a problem are not checked by a professional soon after they develop.
Transmission repairs or replacements are inconvenient, stressful and typically quite expensive, so it’s a good idea to pay attention to any activity that seems unusual. Adhering to the recommended maintenance procedures and schedule intended to prevent problems will help your transmission last longer, perform better and require fewer repairs over its lifespan.
That said, if you’re having some car trouble, it is important to know what the most common types of transmission problems are so that you can easily diagnose them and get them fixed. Here is a list of 10 symptoms of transmission trouble and what signs you should look for.
Lack of Response
Ever notice that while driving that the car hesitates or refuses to go into gear? If you have, then there is definitely something wrong. The moment a driver shifts from park to drive the car should immediately go into the proper gear. For automatic transmissions, you might notice that when shifting into drive or park that there is a delay before you feel the gear engage. This is usually a transmission-based concern.
Manual transmissions can have the same lacking response issue, but after shifting into gear the engine’s RPMs will surge, but the car won’t move as fast as the engine sounds like it’s going. This is usually caused by a clutch that needs to be replaced, but may sometimes point to a more severe problem.
Whining, Clunking and Humming
It’s impossible to say exactly what your car will sound like when there is trouble with your transmission, but one thing is for sure, you’ll get a “I haven’t heard that sound before” feeling when you notice it. The sounds that are produced vary widely between different makes and models, but the best way to describe them is that you’ll probably hear a humming, buzzing or whining noise.
Manual transmissions will emit sounds that can be described as being slightly more mechanical, louder and abrupt sounding. A clunking sounds when you shift gears almost always lies within a transmission, while constant velocity joins or the differential may be the source if the clunking is coming from the underside of your car.
As mentioned already, it is always best to get the problem diagnosed and repaired as soon as possible and not wait until later when you “find the time” or “have the money”. If you wait until later what would have been a relatively inexpensive repair can easily become a much more costly one.
Leaking/Low Fluid
New Automatic Transmission FluidA leak is probably the most recognizable symptom and should be repaired as soon as possible. Letting the fluid leak is one of the most common causes transmission break down. Automatic transmission fluid (ATF) is the life-blood of a transmission as it lubricates, cleans and conditions the seals and acts as hydraulic fluid. Without it (or even if it gets too low), the engine will seize up and stop working completely.
ATF is bright red in color, clear and smells somewhat sweet if everything is working correctly. If this is what you find on your driveway, then all that needs to be fixed is the hole. If the fluid is dark and/or has a burnt smell then it’s time to get the fluid changed or flushed and repairs might be required.
To check if you’re running low on fluid, take your car for a short drive to warm it up and then lift the hood and read the dipstick (be sure the vehicle is on level ground). Unlike motor oil, transmission fluid is not burned off or consumed by a car so if the level is low then there is a leak somewhere that must be patched. It is recommended to top up the fluid anyway even if the leak still exists to make sure there is enough fluid for the transmission to function properly until you get it fixed.
To check the fluid level for a manual transmission, you must check at the transmission case (usually through the fill plug) – not with a dipstick under the hood.
Grinding or Shaking
A car is supposed to run smoothly and without any shaking, or jerking, and there is not supposed to be any grinding sounds. These all suggest that there is a problem with the gears. Manual transmissions commonly indicate problems by making a grinding noise or feeling when you shift into a gear. If the grinding occurs after engaging the clutch and shifting, this can be sign that the clutch may need to be replaced or adjusted. That said, it can also point towards several other issues including damaged or worn out gear synchronizes.
Automatic transmissions act a little differently. Instead of making a grinding noise, you will likely feel it take some time to wiggle into gear at first instead of the typical smooth transitions. As the problem gets worse, the transitions into the next gear become more jarring and involve more shaking. There are a few other reasons for grinding or shaking, but the appropriate course of action is still to have it inspected and serviced.
Burning Smell
Any burning smell coming from your car is a cause for concern. Overheating transmission fluid is one of the causes of a burning smell. Transmission fluid helps keep the parts lubricated and cooled so that they don’t get worn out and damaged.
If the fluid breaks down, the system runs too hot which it results in increased friction and corrosive activity as well as the build up of additional sludge and debris. If this is not taken care of, the transmission will eventually damage itself enough to break down completely. The end result is an expensive replacement. Common causes include low fluid level or using the incorrect brand/type of fluid. To check for these, see the instructions in the section on Low/Leaking Fluid above.
Refuses to Go Into Gear
If the car will not shift after engaging the clutch and trying to move the stick, take a look at the fluid to make sure that it is at the right level. Other causes include using the incorrect thickness (type) of fluid and the clutch linkage or shift cables needing adjustment. The source of the problem could also be the vehicle’s computer system.
If you’ve already inspected the fluid, you can try resetting it. To do this, detach the battery and let it stand for thirty minutes. Then, reattach and allow the system to reset itself. This usually takes around thirty minutes. If this doesn’t work either, then it’s time to take it to a mechanic.
Check Engine Light
Check Engine LightThe check engine light located on your car’s dashboard is a great early indicator that something is about to go wrong (or already has) with your car, and in particular with your transmission. While the light turns on for a number of reasons other than transmission issues, it very important not to ignore this helpful warning sign.
There are sensors placed in many areas of a car’s engine that alert the computer if it senses unusual activity coming from a particular process. The sensors on a transmission can pick up on the slightest jerks and vibrations than you are not able to see or feel.
Take the vehicle in and have it inspected. They can take look and immediately tell what is happening through the use of similar diagnostic tools and the car’s computer.
If you’d like to diagnose the problem yourself (and possibly save yourself a trip to the mechanic’s) you can buy a diagnostic scan tool that is plugged into the instrument panel on the driver’s side and return a code that corresponds to the part that needs attention. Whatever you do, do not assume that the check engine light can wait because it might be warning you of a serious problem in the near future.
Transmission Noisy in Neutral
Luckily, a transmission that is noisy (goes “bump”) when it is in neutral could have an inexpensive, simple solution such as adding some fluid or changing it. This could do the trick, as it does for several other issues on this list. If that doesn’t work, the transmission may require professional attention to replace worn out parts, most commonly the bearings, worn gear teeth or the reverse idler gear.
Gears Slipping
A transmission stays in a designated gear until a shift is performed by the driver (manual) or the computer (automatic). If the transmission is spontaneously slipping in an out of gear (or simply popping into neutral) while driving, I don’t need to tell you that this is a serious safety risk. When you need to step on the gas to avoid a dangerous situation, you need power delivered to the wheels, end of story. The cause can be the link that holds the gears is worn or broken. Get your car inspected and repaired as soon as possible.
Dragging Clutch
A dragging clutch describes the symptom experienced by manual transmissions that involves the clutch disk failing to disengage the flywheel when the clutch pedal is pressed. The clutch is still spinning with the engine which makes it anywhere from difficult to impossible to change gears. This difficulty is accompanied by a grinding noise each time you try to change gears.
Fortunately, this problem is considerably less expensive to repair than many other issues. More often than not, the cause of this is too much slack in the clutch pedal. With too much slack available, the linkage between the clutch disk and pedal can’t pull the clutch disk away from the flywheel.
Conclusion
It is important to keep up a regular maintenance schedule for your car. Many times major expensive repairs can be avoided if the vehicle is properly maintained. This is especially true if you notice something unusual. The car should be taken in immediately for service.
Brushing up on your knowledge of transmissions (at least the basics) is highly recommended as it can help you save money by avoiding costly inspections and doing simple procedures such as changing transmission fluid yourself as well as making you knowledgeable enough to avoid being over-repaired, over charged or simply ripped off.
Monday, 27 March 2017
Symptoms of a Bad or Failing Transmission Speed Sensor
Common signs include harsh or improper shifting, cruise control not working, and the Check Engine Light coming on.
The transmission speed sensors are used to calculate the actual gear ratio of the transmission while in use. There are generally two speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s powertrain control module. The first is known as the input shaft speed (ISS) sensor. As described, this sensor is used to monitor the speed of the transmission' input shaft. The other sensor is the output shaft speed (OSS) sensor. If either of these two sensors falls out of alignment or experiences electrical issues, it impacts the operation of the entire transmission.
After registering data, the two transmission speed sensors, also commonly referred to as a vehicle speed sensors (VSS), send data to the powertrain control module (PCM), which compares these two inputs and calculates which gear the transmission should engage for efficient driving. The actual gear ratio is then compared to the desired gear ratio. If the desired gear and the actual gear do not match, then the PCM will set a diagnostic trouble code (DTC) and illuminate the Check Engine Light.
Should either or both of these speed sensors fail, you may notice one or more of the following issues:
1. Harsh or improper shifting
Without a valid speed signal from these sensors, the PCM will not be able to correctly control the shifting of gears within the transmission. This may cause the transmission to shift roughly or more quickly than normal. It's also common that a problem with these sensors can impact the shift timing, extending the interval between transmission shifts. An automatic transmission is hydraulically controlled and designed to shift smoothly.
When the transmission shifts hard, it can damage internal components including valve bodies, hydraulic lines, and in some cases mechanical gears. If you notice that your transmission is shifting harshly or roughly, you should contact a local ASE certified mechanic as soon as possible.
2. Cruise control does not work
Since the transmission speed sensors monitor the input and output shaft speed, it also plays a part in monitoring the cruise control. When the sensors fail to deliver accurate data to the onboard computer on your car, truck, or SUV, the powertrain control module (PCM) will send an error code to the vehicle’s ECU. As a safety precaution, the ECU will shut down the cruise control and render it inactive. If you notice that your cruise control does not engage when you press the button, contact a mechanic so they can inspect the vehicle and determine why the cruise control is not working. It may be due to faulty transmission speed sensors.
3. Check Engine Light comes on
If the signals are lost from the transmission speed sensors, the PCM will set a DTC and illuminate the Check Engine Light on the vehicle dashboard. It also can indicate that there is an increase in tailpipe emissions is occurring that surpasses acceptable limits for environmental contaminants from motor vehicles.
In any case, if you notice that the Check Engine Light comes on, you should contact a local mechanic to scan the error codes and determine why the Check Engine Light is illuminated. Once the problem has been fixed, the mechanic will reset the error codes.
If the problem rests with the speed sensors, depending on your particular transmission, the professional ASE certified mechanics from AutoFactorNG may be able to replace the sensor. Some speed sensors are internal to the transmission and will require the transmission to be removed from the vehicle before the sensors can be replaced.
The transmission speed sensors are used to calculate the actual gear ratio of the transmission while in use. There are generally two speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s powertrain control module. The first is known as the input shaft speed (ISS) sensor. As described, this sensor is used to monitor the speed of the transmission' input shaft. The other sensor is the output shaft speed (OSS) sensor. If either of these two sensors falls out of alignment or experiences electrical issues, it impacts the operation of the entire transmission.
After registering data, the two transmission speed sensors, also commonly referred to as a vehicle speed sensors (VSS), send data to the powertrain control module (PCM), which compares these two inputs and calculates which gear the transmission should engage for efficient driving. The actual gear ratio is then compared to the desired gear ratio. If the desired gear and the actual gear do not match, then the PCM will set a diagnostic trouble code (DTC) and illuminate the Check Engine Light.
Should either or both of these speed sensors fail, you may notice one or more of the following issues:
1. Harsh or improper shifting
Without a valid speed signal from these sensors, the PCM will not be able to correctly control the shifting of gears within the transmission. This may cause the transmission to shift roughly or more quickly than normal. It's also common that a problem with these sensors can impact the shift timing, extending the interval between transmission shifts. An automatic transmission is hydraulically controlled and designed to shift smoothly.
When the transmission shifts hard, it can damage internal components including valve bodies, hydraulic lines, and in some cases mechanical gears. If you notice that your transmission is shifting harshly or roughly, you should contact a local ASE certified mechanic as soon as possible.
2. Cruise control does not work
Since the transmission speed sensors monitor the input and output shaft speed, it also plays a part in monitoring the cruise control. When the sensors fail to deliver accurate data to the onboard computer on your car, truck, or SUV, the powertrain control module (PCM) will send an error code to the vehicle’s ECU. As a safety precaution, the ECU will shut down the cruise control and render it inactive. If you notice that your cruise control does not engage when you press the button, contact a mechanic so they can inspect the vehicle and determine why the cruise control is not working. It may be due to faulty transmission speed sensors.
3. Check Engine Light comes on
If the signals are lost from the transmission speed sensors, the PCM will set a DTC and illuminate the Check Engine Light on the vehicle dashboard. It also can indicate that there is an increase in tailpipe emissions is occurring that surpasses acceptable limits for environmental contaminants from motor vehicles.
In any case, if you notice that the Check Engine Light comes on, you should contact a local mechanic to scan the error codes and determine why the Check Engine Light is illuminated. Once the problem has been fixed, the mechanic will reset the error codes.
If the problem rests with the speed sensors, depending on your particular transmission, the professional ASE certified mechanics from AutoFactorNG may be able to replace the sensor. Some speed sensors are internal to the transmission and will require the transmission to be removed from the vehicle before the sensors can be replaced.
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