Hard Shifting Automatic Transmission: let’s begin with the most important advice of the entire article; If you are experiencing problems with a hard shifting automatic transmission, get your vehicle to a mechanic as soon as possible. If you just started noticing rough gear changes with your automatic transmission, you did the right thing by choosing to read this article. We will list the most common reasons for a hard shifting automatic transmission and you can narrow down the issue you are having.
In any case, an automatic transmission is not made to change gears roughly. Any sign of rough shifting is a clear sign of trouble. The longer you ignore that problem, the bigger the damage and the repair bill are going to be.
Reasons for hard gear shifts with an automatic transmission
We will list the reasons in an order from the most common and cheapest to repair and all the way down to the reasons you do not want to experience.
You might not even be at fault. If you take well care of your automatic transmission, sometimes the reason for hard shifts is just extremely cold weather. Before your automatic transmission warms up and properly lubricates, the gear changes might not be as smooth as expected. Cold temperatures thicken the transmission fluid which means it needs some time to warm up and set to the viscosity level it needs to be at. The best way to warm up your transmission is not to let the car idle, you should just take it easy on the transmission until you can feel it is warmed up.
Not enough transmission fluid
One of the most common reasons for hard gear shifts with an automatic transmission is a lack of transmission fluid. A lack of transmission fluid is usually connected to some sort of a leak. A healthy automatic transmission will not leak fluid because it is generally a tightly sealed unit. A leak can occur in multiple places on the automatic transmission itself. The most common place for a leak is the gasket, followed by the fluid lines, transmission pan seals, and the torque converter.
You will eventually see transmission fluid on the ground where you usually park your car. Transmission fluid is thicker than engine oil and if it is in good condition it should be red in color. Another way to differentiate transmission fluid leaks from engine oil leaks is to look at the location of the leak on the ground. The automatic transmission is located further back from the engine which is where you can expect the leak to be.
If you notice even anything you might suspect to be transmission fluid, go to your mechanic for a check-up as soon as possible. The sooner you take care of a potential leak, the better. Trust us. Getting a 150$ transmission seal or gasket replaced is much cheaper than fixing an automatic transmission that runs on a deficient amount of transmission fluid.
Worn out transmission fluid or oil
Transmission fluid is not a lifelong fluid, even if some car manufacturers tend to say so. Every transmission fluid needs to be replaced at some point. The most automatic transmission should have their transmission fluids replaced every 30,000-60,000 miles (50,000-100,000 km). It depends on the transmission and the driving scenarios. A car that only covers highway miles is going to put less stress on the transmission fluid than a truck hauling heavy loads on a daily basis.
You should consult your mechanic but never agree to the fact that some car manufacturers say it is ok to not change the transmission fluid, it is complete nonsense.
The transmission fluid’s objective is to lubricate and cool all the moving parts inside an automatic transmission. And there are a lot of moving parts in every type of automatic transmission. Once the transmission fluid gets worn out, it no longer lubricates the moving parts. It loses its viscosity, becomes watery, and is contaminated with particles of unproperly lubricated moving parts of the transmission. Along with that, the transmission can overheat and the rising temperature can cause further damage.
Wrong transmission fluid
Modern automatic transmissions are precise units that require the exact transmission fluid as it is prescribed by the car manufacturer, or better yet, the transmission manufacturer. Filling the automatic transmission with an incorrect transmission fluid can lead to the same problems as having a worn-out transmission fluid.
We advise you to always use an automatic transmission specialist for any work that is being done on the transmission. Simple errors like choosing a generic transmission fluid can lead to much bigger repairs costs. Read more about the right transmission fluids for you here.
Damaged transmission components
Several transmission components might be at fault when experiencing hard shifting with your automatic transmission. These include: damaged torque converter, damaged clutch plats and even shift slide problems. If you regularly replace your transmission fluid then one of these components might be the culprit behind the problem.
Damaged sensors or TCU (Transmission Control Unit)
The transmission control unit or TCU gathers data from various sensors to determine the next step for the automatic transmission. If the TCU is damaged, or there are faulty sensors that are sending no information or false information the result can be rough shifting, delayed shifting or premature shifting. An example would be the Mercedes-Benz 7G 722.9 automatic transmission which was known for having problems with speed sensors on the TCU which resulted in hard, jerky shifts.
Transmission vacuum problems
Vacuum modulator and vacuum lines are responsible for recognizing the load you are putting on your car. By measuring the workload, the pressure gets sent to the vacuum modulator which in return triggers the gear change process. Damaged vacuum lines can make the shifting harder and rougher. This problem should be addressed as soon as possible to avoid the possibility of having the entire vacuum modulator replaced.
Worn-out automatic transmission
If your car and automatic transmission have covered a large number of miles (we are talking 300,000 miles and more), chances are, that your transmission has just had enough. There comes a time when so many interior components of transmission get used up even when maintained properly that you simply need a transmission rebuild or a replacement.
Hard shifting when going from Park to Drive
The most common problem for hard shifting when going from Park to Reverse, Neutral or drive is a faulty interlock switch. The interlock switch releases the parking pawl and engages the brake lights. If the interlock switch is at fault, the brake lights do not receive the signal, and you arent able to switch from Park into other positions.
Other reasons include:
- Damaged or dirty shift cable linkage that leads from the shifting lever to the transmission.
- Worn out transmission fluid
- A lack of transmission fluid
- You park on an incline and the parking pawl has a bigger load to disengage
Frequently asked questions
I am experiencing hard shifting with an automatic transmission when it is cold, is it normal?
Yes, if it really only happens when the temperatures are freezing, then it is considered to be normal.
Is hard shifting bad for a transmission?
Yes, it most certainly is. The longer you ignore the hard shifting the worse it will get and you also risk of causing serious damage to your automatic transmission.
What does it mean when the transmission shifts hard?
It means that something in the transmission is not functioning as it should. The most common reasons include: worn-out transmission fluid, a lack of transmission fluid and problems with the transmission control unit and the sensors that provide the data for correct gear shifts.
How to fix hard shifting automatic transmission?
There is no simple answer. Your transmission needs to be diagnosed by a professional to determine the problem and solve the underlying reason. In most cases, a replacement of transmission fluid will solve the issue.
What causes hard transmission gear shifts?
The most common reasons include: not enough transmission fluid, worn-out transmission fluid, problems with the transmission control unit, problems with the input sensors and problems with other transmission components.
Can I fix a hard shifting automatic transmission by using additives?
In most cases no, using additives only resolves the issue temporarily which is never a good idea for the long-term health of your automatic transmission. Anti-leak additives are also not a long-term solution to transmission fluid leaks.
Do these reasons apply to DSG automatic transmissions?
Yes, they do. DSG or dual-clutch automatic transmissions still use transmission fluid and transmission control units to determine gear shifts. Nearly all the reasons for hard shifting listed above also apply to DSG transmissions.
If you read the article you already know what we are going to say. For your own peace of mind and for the well-being of your automatic transmission, be sure to keep your automatic transmission regularly serviced. Make sure that you have your transmission fluid and filter changed within a regular interval. Ask your mechanic to check the state of your transmission fluid every time you change your engine oil and make sure he also checks the automatic transmission for any leaks. If you live in areas with freezing temperatures, be sure to give your transmission the time to warm up. And lastly, do not ignore any issues with your automatic transmission because it will only get worse and more expensive to repair. All the best!
If you have any other automatic transmission problems, check out our guide to the 14 most common automatic transmission problems.