Top 8 Causes of Transmission Slipping | How to fix a Slipping Transmission?

The transmission is one of the most important parts of your car. Preventing transmission problems is very important to avoid expensive repairs. However, issues with your car transmission can occur unexpectedly. One common problem that leads to an expensive repair is a slipping transmission. There are various reasons of a slipping automatic transmission system. This article mainly explains why your automatic transmission is slipping. Let’s explore the causes!

What Does a Slipping Transmission Mean?

A slipping transmission refers to the improper shifting and engagement of gears in an automatic transmission, resulting in a lack of synchronization between the transmission speed and engine speed. It can be likened to a slipping clutch in the manual transmissions.

The automatic transmission of your vehicle consists of planetary gear sets, a valve body, and a torque converter.

Understanding the causes of slipping transmission can aid in their prevention. If your vehicle has a manual transmission, it is important to pay attention to the feel of your clutch.

In the case of an automatic transmission, slipping can begin due to wear and tear on various components. These parts may include damaged solenoid packs, transmission bands, and clutch plates.

When addressing a slipping automatic transmission, a professional is likely to replace some or all of these parts to rectify the issue.

Slipping Transmission Causes

The transmission of your vehicle slips due to one or more of the below-given reasons:

Low Transmission Fluid
Burnt Transmission Fluid
Broken Transmission Bands
Bad Solenoid
Faulty Torque Converter
A Slipping Clutch
Gears
Software and Sensors

1) Low Transmission Fluid

Insufficient transmission fluid is one of the most frequent causes of automatic transmission slipping. However, it is easy to fix.

When the transmission fluid becomes too low or too high, the transmission cannot function properly.

If your transmission is slipping, it is likely that the transmission fluid is either low or dirty. A decrease in fluid level reduces the necessary pressure for proper gear engagement, resulting in strain while shifting, leading to slipping and overheating of the transmission fluid.

Likewise, aged or contaminated fluid, as well as a clogged transmission filter, may also cause transmission slips. A filter or fluid change, or in more severe instances, a flush, may also resolve many issues.

Checking the transmission fluid is usually a straightforward task. You can use the dipstick located in the engine compartment or refer to your service manual for instructions about transmission fluid checking.

2) Burnt Transmission Fluid

The burnt transmission fluid is one of the major reasons for the transmission slipping. The burnt fluid emits a distinct burnt toast odor and appears unusually dark in color. Burnt fluid becomes ineffective, affecting various transmission functions and resulting in slipping.

If the transmission fluid smells burnt, it is essential to change it promptly and address any faulty transmission components causing the issue.

Burnt transmission fluid typically occurs due to transmission overheating, but it may also be a combination of very old fluid and high fluid temperature. Worn components may also contribute to the presence of black transmission fluid that requires replacement.

3) Broken Transmission Bands

Transmission bands are internal parts of the transmission system that serve to disengage or engage the gears in a transmission. Over time, these bands can wear out, necessitating adjustments.

In the past, the adjustment of the transmission bands was a common part of scheduled maintenance, particularly with older transmissions.

However, in modern times, it is uncommon to have to replace these bands throughout the lifespan of a vehicle. In the rare event that replacement is necessary, it typically requires a complete transmission rebuild. It is preferable to replace the broken bands individually rather than the entire transmission.

However, these bands are not installed in all transmission types. Therefore, it is worth considering when investigating the reasons why your transmission is slipping.

4) Bad Solenoid

A bad shift solenoid is also a most frequent reason of the transmission slipping. A shift solenoid is an electronic valve that is responsible for regulating hydraulic pressure to ensure the precise timing of shifts in the transmission.

If these solenoids falter, the transmission parts do not receive the necessary fluid pressure to engage properly. Consequently, bad solenoids may also lead to improper engagement of clutches and bands, resulting in slipping.

5) Faulty Torque Converter

The torque converter serves as the main connection between the transmission and the engine. When it becomes faulty, your transmission may show symptoms of slipping.

Filled with transmission fluid, the torque converter utilizes this fluid to transform engine power into torque to turn the vehicle wheels.

A major issue with the torque converter is the failure to produce sufficient pressure to transmit torque effectively, resulting in a slipping transmission.

6) Slipping Clutch

Contrary to popular belief, the clutch is only located in the manual car. In reality, even modern automatic transmissions incorporate clutches.

In fact, multiple latest gearboxes are essentially manual transmissions with automated shifting mechanisms managed by a robot rather than manual input from the driver.

7) Gears

Gears function by interlocking sets of teeth that grip and propel each other. If these teeth become worn down because of different factors like general wear and tear, age, or insufficient transmission fluid, they may fail to mesh properly or transmit power effectively. This can result in slippage.

While it is uncommon for gears in automatic transmissions to wear out before the clutches and bands. If such wear occurs, it necessitates an expensive repair or replacement.

8) Software and Sensors

Although computers have advanced capabilities, but they still rely on human programming. Artificial intelligence plays a role in enhancing computer systems, but without it, limitations persist.

Errors in the transmission control module programming or signals from different vehicle sensors may cause transmission slipping.

What is a Transmission?

A transmission serves as the connection between the engine and the wheels, facilitating the transfer of power from the engine to the wheels to propel the vehicle.

It ensures the engine speed is matched to the vehicle’s speed by utilizing different gears, enabling forward and reverse motion according to the selected gears.

The three most prevalent types of transmissions found in common vehicles are the continuously variable transmission (CVT), traditional automatic transmission, and manual transmission.

The manual transmission of your vehicle needs the use of a clutch pedal and involves the driver manually selecting gears using a gear shifter. In contrast, automatic transmissions operate without a clutch pedal and automatically shift through their gear sets.

How To Fix a Slipping Transmission

To address a slipping transmission, it is essential to follow a systematic approach:

Start by checking the level of the transmission fluid and wisely examining its condition.
If your transmission fluid is insufficient but appears to be in good condition, try adding fluid to the appropriate level.
If the fluid is brown, it indicates potential contamination, and it is advisable to replace the filter and the fluid.
In the case of black or burnt-smelling fluid, immediate fluid replacement and a transmission flush are recommended.
It’s important to note that if the transmission is slipping, the internal parts of the transmission may be worn or damaged. Some worn-off friction material, such as from clutches, may be circulating within the used fluid. Although not ideal, this material may still contribute enough friction to maintain transmission functionality. Replacing the fluid in this scenario may worsen the slipping issue.
You may also use a scan tool to read the TCM to retrieve any trouble codes. Focus on identifying potential issues related to the shift solenoid.
If you have changed the fluid and performed all other repairs, but the problem still persists, it is advisable to consult a professional specialist for a comprehensive inspection and possible transmission rebuild.

FAQ Section

Can a Transmission Flush Fix Slipping?

Yes, insufficient or low transmission fluid is one of the major causes of automatic transmission slipping, and the transmission flush can fix it. But it’s important to note that a complete fluid flush is typically best performed using professional tools at an automotive shop. This process ensures the removal of every last drop of fluid, and it is not a straightforward task suitable for a home garage setting.

How to Prevent Transmission Slip?

Ensure the sufficient level of the transmission fluid. If the fluid is dirty, change it as soon as possible.
Ensure the good condition of your engine with regular maintenance, such as fuel system maintenance, air filter change, and spark plug replacement.
Ensure the proper maintenance and service of your transmission system.
Use the transmission fluid according to the vehicle manufacturer’s instructions. Avoid using the wrong fluid.
Replace your transmission fluid and filters according to the vehicle manufacturer’s recommendation.
Avoid overloading or excessive towing.
You should let the transmission and engine warm up for some time before driving in a cold climate. This assists in ensuring proper lubrication and fluid circulation.
When switching between park, reverse, or drive, make sure the car comes to a complete stop before shifting.
You shouldn’t drive your vehicle aggressively or suddenly.

Can I drive my car with a slipping transmission?

Driving a car with a slipping transmission is strongly discouraged. When your transmission slips, it generates excessive heat in the transmission fluid, leading to potential damage and burning of costly transmission components.

Is transmission slipping a safety risk?

A slipping transmission poses considerable dangers. Not only does it create an unpredictable gear-shifting pattern, but it also causes the car to become shaky and challenging to control. This compromises the overall safety of the vehicle and increases the risk of accidents.

Is a slipping transmission serious?

Transmission slipping is a concerning issue that should be addressed promptly to ensure safety and prevent additional damage to the transmission. If you are experiencing this problem, it is highly recommended to have your car inspected by a qualified mechanic without delay.

What happens when an automatic transmission slips?

Although automatic transmissions are more commonly associated with slipping, they can also occur in manual transmissions. When your transmission slips, it fails to shift gears as intended or may engage gears unexpectedly.

Can Torque converter issues cause the transmission to slip?

Yes, a bad torque converter is one of the major causes of a slipping transmission.

Written By

Engineer Rahela

Rahela is the owner and main author of Mechanicalspecial. She is an automotive expert writer. She have over four years of experience in the automotive writing niche and have completed over 700 pieces of content from 40 projects. She have good knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance.