The transmission sometimes doesn’t want to shift into overdrive .

The transmission sometimes doesn't want to shift into overdrive , and when you stop the speedometer will go up and down .

My car has 153000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi there. There are several potential reasons why the transmission on your 2002 Town & Country does not shift into overdrive. This could be caused by low transmission fluid, a blockage in the transmission lines, or a transmission sensor. The fact that the speedometer goes up and down might indicate a problem with the speedometer sensor, which is attached to the transmission and relays info to the ECU to help the transmission shift as well as send signals to the speedometer.

A good idea would be to contact a local ASE certified mechanic to test drive your Chrysler and then diagnose the hard shifting issue for you.

How to Identify and Fix Common car Problems ?

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Possible causes of no overdrive include a faulty transmission range switch, valve body, faulty overdrive brake, or faulty ECM. Faults codes should be read out with a scanner, and statuses read.
Sometimes, the problem can be as simple as a bad transmission pan gasket, but it can also be faulty seals, ruptured fluid lines, a leak in the pan or a crack in the torque converter.
The Transmission Range Sensor tells the PCM the position of the transmission shifter. The PCM uses this information to control which gears of the transmission to enable or disable. When the TR sensor fails it can cause wrong gear starts, no upshifts, or what feels like a falling-out-of-gear condition.
The primary time to turn overdrive off is when going up or down a steep hill. Both of these situations merit being in a lower gear. When going down a hill, using a lower gear helps your vehicle engine brake. This lets the engine do some of the work for you without wearing out or overheating your brakes.
Make sure you`re using the latest version of the OverDrive app by going to the App Store and checking for updates. Close the OverDrive app completely by swiping it up from your app switcher. Restart your device. Contact support for more help, and let them know you tried all the steps in this article.
With an automatic transmission, overdrive is most often an intuitive function initiated by the ECU when the vehicle reaches the proper speed. In the case of manual transmissions, overdrive is the highest gear of the transmission but has to be engaged by the driver.
Bad Transmission Control Module Symptoms

Slow Acceleration: It takes longer than normal for your vehicle to pick up speed. Gear Slippage: Your transmission switches gears without warning or without you shifting. Inability to Shift: You can`t shift out of neutral.

If your transmission position sensor is failing, your transmission may become locked in an unchanging gear. This condition is known as limp mode, and a car that has gone into limp mode is suffering from severe transmission issues.
For example, in some situations an oxygen sensor can cause poor shifting in your transmission – if the engine isn`t running correctly, the transmission control module may misinterpret when and where it`s supposed to be shifting, causing erratic behavior at the transmission.
Switching the overdrive off on the Villager only effects the transmission`s ability to shift into overdrive – it effectively becomes a three-speed transmission, the top gear being direct drive.
However, in general, it`s probably not a good idea to tow in overdrive because the transmission could overheat and cause damage.
Usage. Generally speaking, overdrive is the highest gear in the transmission. Overdrive allows the engine to operate at a lower RPM for a given road speed. This allows the vehicle to achieve better fuel efficiency, and often quieter operation on the highway.
Once acceleration levels off, the torque converter locks into the higher overdrive gear, effectively changing the gear ratio so that your car can travel faster at lower engine RPMs. You can feel the change as your engine relaxes when you ease off of the throttle to stop accelerating.
Technically speaking, a direct drive is more efficient in top gear than an overdrive due to its ability to transmit power directly through the main shaft with minimal parasitic losses.
An Overdrive is a component of a transmission system which is attached at the end of the gear box in order to provide highest gear output with minimum engine input which in turn makes the drive smooth and more fuel efficient.
Now, this longtime digital reading companion will be shutting down for good. After announcing its plans to sunset the app and removing it from app stores last year, the company now says that OverDrive will fully shut down on May 1, 2023. Readers will be directed to use the newer digital app Libby instead.
When a hold becomes available for you, you`ll receive an email and a notification in your library`s OverDrive collection. You have 72 hours to borrow the hold or have it delivered later if you`re not ready to read it.
The best thing to do to confirm the problem is to test the torque converter. To test the torque converter, you must step on the pedal to the floor and accelerate your engine for up to five seconds. The reading for the revolutions per minute (RPM) will max out at the stall speed.
Your vehicle seems to have trouble downshifting when your vehicle slows down. Your vehicle`s engine roars loudly and has difficulty shifting to higher gears when you attempt to accelerate. Your vehicle`s gears shift unexpectedly to another gear or neutral when you`re driving.
The output speed sensor is also known as the vehicle speed sensor in a vehicle. It transmits a signal to the transmission control unit, informing it of the vehicle`s speed. Failure of the speed sensor is a common reason for taking the car to the mechanic.
Typically, two sensors communicate the transmission data to the vehicle`s powertrain control module. The first sensor, referred to as the input sensor, monitors the speed of the transmission`s input shaft. The second sensor is the output sensor, which monitors the output shaft speed.
If your overdrive is working, the engine speed should fall by 500 or more rpm without a reduction in the vehicle`s speed.
The downstream or diagnostic sensors only monitor the exhaust leaving the catalytic converter and will not cause such an issue. Other symptoms of a bad oxygen sensor include a rough idle, a misfire, and/ or hesitation when trying to accelerate.
For the most part, anything that affects the engine performance will lead to trouble shifting gears in your car. A clogged catalytic converter makes the engine work harder, which in turn makes it difficult to shift the transmission.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

The transmission sometimes doesn’t want to shift into overdrive .
ANSWER : Hi there. There are several potential reasons why the transmission on your 2002 Town & Country does not shift into overdrive. This could be caused by low transmission fluid, a blockage in the transmission lines, or a transmission sensor. The fact that the speedometer goes up and down might indicate a problem with the speedometer sensor, which is attached to the transmission and relays info to the ECU to help the transmission shift as well as send signals to the speedometer.

A good idea would be to contact a local ASE certified mechanic to test drive your Chrysler and then diagnose the hard shifting issue for you.

it doesn’t want to shift into reverse sometimes and it doesn’t want to shift up to the next gear without letting off on the gas why
ANSWER : Hello. It sounds like the car has a valve body issue. Most of the time, this is caused by one of the valves getting hung up in the transmission valve body or one of the solenoids sticking. I usually scan the computer for codes first to see if anything comes up. If not, then I test the pressures of the transmission to see if it is an electrical issue or a mechanical issue. Either way it would be best for you to get some help from a transmission specialist with this. If you would like to have this checked, a qualified professional from YourMechanic can come to your home or office to diagnose the shifting issue and pinpoint the problem.

Truck will shift sometimes then it doesn’t shift. If you wait a while it will shift again. We are trying to figure out what’s going on
ANSWER : Hi, thanks for writing in. The first thing I recommend is to make sure the ATF (automatic transmission fluid) is full.

Does the transmission shift up a gear or two and stay in that gear, or does it drive fine for a bit, then stop shifting until you turn the car off or sit still with the motor running? Or, do you continue to drive and eventually it begins shifting again. Are there any codes?

What I would do if I were diagnosing your truck would be to connect a scanner and study the data while driving to know what is going on. Without said data and not quite being clear about what is happening, it comes down to solenoids or sensors that the TCM (transmission control module) uses to calculated shift points based on load values determined by the PCM (powertrain control module).

I’m afraid all I can offer you at this point is suggesting you make sure the fluid is full and clean. If it isn’t clean, begin by replacing the filter in the pan and do a transmission fluid exchange, not just pan drop with a drain and fill. This doesn’t get all the ATF out of the transmission, and when there are problems, it pays to be as thorough as possible.

I recommend the following inspection if you should need further assistance: Car hard to shift

Hope this helps and best of luck!

When I start my truck it’s idling high and when I’m driving the rpm fluctuate up and down and the transmission doesn’t want to
ANSWER : Hello. It sounds like you may have a vacuum leak. This engine is notorious for vacuum leaks from a bad intake manifold gasket. This is very common. It can also be from the MAP sensor or a number of other things. I usually test for vacuum leaks first as I have seen this the most. If you want to have this checked out by a professional, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the high idle and hard shifting so that these issues can be properly addressed.

Nissan Serena 2001 Transmission has shifting-problems intermittently.
ANSWER : It is possible that this is a transmission control module issue. As you may already know the transmission control module provides direction to the transmission as to shifting points, clutching and a wide variety of other control related transmission functions. Check to be sure there is a proper amount of transmission fluid in it. I would suspect that based upon your descriptions there is most likely a Check Engine Light on in your dash. This will register a fault code in the car’s computer which will provide detail as to the specific problems the transmission may be having. You will need a specific type of scanning tool that works directly with the transmission ECM rather than your car’s main computer. I would recommend having an expert from YourMechanic come to your home to diagnose your possible faulty transmission and make repairs.

Transmission intermittently won’t shift to next gear
ANSWER : It is very possible that the transmission may require a full rebuild or a replacement in order for it to perform properly. Although you are able to shift into other gears, if certain gears are not working correctly, transmission damage may be the cause.

If the transmission has already been diagnosed by the dealer that it needs replacement and the transmission is still not shifting properly, it is unlikely that the transmission will get any better without replacement.

It does not hurt to attempt any reset procedure that may be available, but it is also unlikely that a reset of any kind will resolve transmission issues. Small things to check before replacing the transmission if possible would be the fluid level and any trouble codes that may have been stored due to the issue your transmission is causing.

If any codes exist, this may lead you to other possible parts inside the transmission that may be able to be replaced and have your transmission working again as it should. You can get a second opinion from an local expert, such as one from YourMechanic, in order to diagnose your shifting problem and advise you on the next steps.

The transmission keeps dropping out of overdrive.
ANSWER : Hi there. If the transmission is coming out of overdrive and back into overdrive, either the downshift solenoid has an internal leak or there is an internal issue with the transmission overdrive clutch. Check the downshift solenoid and see if it’s functioning. To do this, slow down the vehicle and see if the rpm’s slightly raise up as the vehicle descends to a stop. If the rpm’s are not raising up as the vehicle is slowing down, then I recommend replacing the downshift solenoid. If the rpm’s raise up, then there is an internal part failure in the transmission. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your transmission.

Transmission issues, rough shifting and noise
ANSWER : Many different faults can cause the vehicle to shift roughly. The most common would be low fluid level in the transmission, transmission mounts, the torque converter, or one of the shift solenoids. If you’d like to get this checked before moving forward with a repair, a qualified technician, such as one from YourMechanic, will be able to diagnose your shifting issue and perform any repairs required.