Transmission Fluid Leak: Everything You Need To Know

Transmission fluid is a lubricant that helps the transmission work properly. If there is damage to the transmission or any of its components, a transmission leak can occur. If not repaired, it can lead to further problems.

If you own or drive a vehicle, you may eventually have to deal with a transmission leak. While leaks are common and many are easy to repair, a leak can also be a sign of a more serious problem. Many things can cause a transmission fluid leak, and if you do not fix the problem quickly, it can lead to severe problems for your vehicle.  If you have a transmission leak or suspect you may have one, take your car to a mechanic for repairs as soon as possible.

What Does Transmission Fluid Do?

Transmission fluid is a type of lubricant that helps keep the moving mechanical pieces of a car from grinding together and breaking down. It can also help prevent overheating in vehicles with automatic transmissions. Some other functions of transmission fluid include,

  • Cleaning the metal surfaces
  • Protecting metal components from wear
  • Reduce operating temperatures
  • Increase rotational speed and temperature range

Transmission fluid should be checked regularly to make the levels are correct. It can be added to the engine by car owners. You can purchase transmission fluid from auto parts stores and many department stores.

What Are The Different Types of Transmission Fluid?

There are several different types of transmission fluid. Automatic transmissions use automatic transmission fluid. Manual transmissions can use various types of fluid. It is essential to know which type of fluid your vehicle takes, as using the wrong kind could cause mechanical problems. The vehicle’s user manual should offer the exact type of fluid the automobile needs.  The most common types include,

HFM Fluids:  HFM stands for Highly Friction Modified. They work just as the name suggests, and help to reduce friction and the overheating caused by it. They are affordable, but not the cheapest option.

Hypoid Gear Oil: This type of transmission fluid is resistant to extreme temperatures and pressure. It is what most manual transmission use.

Dexron/Mercon: These types are used in most automatic transmission and come in different quality grades. They prevent friction and help protect the transmission components.

Synthetic Fluids: Synthetic fluids are often more expensive than others, but they also work a little better. They are made to withstand oxidation, extreme heat, and friction. They tend to last longer than other types of transmission fluids.  

Motor Oil: While motor oil works best in the motor of a vehicle, if it’s all you have on hand, it can also work as transmission fluid. It is similar enough to transmission fluid that it lubricates the mechanical components without damaging the transmission or causing problems.

Type-F: Type F is made for older, automatic transmission. It does not contain friction modifiers and is not appropriate for all types of transmission systems.

How Do I Add Transmission Fluid To My Car?

If a transmission is leaking fluid, you will need to replace that fluid frequently. Most people can easily add the liquid to their vehicles themselves. The process is relatively simple and only requires a little knowledge of your vehicle.  Just follow these steps,

Step 1: Check the fluid to make sure it is indeed low. To do this, start the vehicle and allow it to run. Use the parking brake to keep your car from moving while you check it. Some cars need to be in the neutral position in order to get an accurate fluid level reading.

Open the hood and pull out the dipstick. Look to see where the levels are on the stick and then wipe it clean and check again. If the levels are low, you will need to add more.

Step 2: Leave the car running and put a funnel in the dipstick hole. Pour the appropriate type of transmission fluid into the funnel slowly and wait for it to funnel into the transmission. Be sure not to add too much at a time, so you do not overflow it.

Step 3: Get back in the vehicle and press the break while moving the gearshift through all the gears. It helps the fluid move throughout the transmission.

Step 4: Check the transmission one more time to ensure that it is at the appropriate levels. If it needs more, add it gradually.

Step 5: Place the dipstick back into the transmission and replace the cap if necessary. Make sure the lid is on tightly as pressure may build under it and cause it to pop off while you are driving. You should notice your car’s performance improve within the next few days. If the transmission problems continue, there may be another issue instead of just a leak.

How Often Should I Change My Transmission Fluid?

Most cars do not need to have the transmission fluid changed frequently. If there is no problem, the transmission fluid in an automatic vehicle should only need to be replaced every 60,000 to 100,000 miles.  Manual transmissions may require more frequent changes at 30,000 to 60,000 miles.

Changing the transmission fluid is not a difficult task, but most people prefer to have a mechanic do it for them. Unless you are confident in your abilities to complete the process, do not attempt it.

What Causes Transmission Fluid Leaks?

Many things can cause a transmission fluid leak. Know the cause of the problem will help you determine how to fix it or decide if you should take it to a mechanic to have it repaired professionally.  Some reasons are obvious, and others are hard to find. Some of the most common include,

Bad Transmission Pan Gasket

Vehicles with automatic transmissions have pan gasket where the transmission fluid is kept. The seal between the pan and the transmission can become corroded and eventually fall apart or even dissolve. When this happens, the fluid can lead out as it transfers from the gasket pan to the transmission.

Cracked Torque Pump

The torque pump circulates the fluid through the transmission.  If the pump stops working, the fluid stays in one spot and can then easily leak out. This can also cause problems with the transmission since the liquid is not making it to all of the gears.

Broken Fluid Line

If the transmission line becomes clogged or breaks, it can cause the fluid to drip or leak out. You may notice a spot of fluid underneath your car when it’s parked, or you may feel your transmission slipping as a result of having no fluid.

Worn Transmission Pan

Transmission pans hold transmission fluids, and after a while, they can become worn out. They may develop holes or cracks that can allow the fluid to leak out. The pans can also rust and fall apart, causing fluid to leak much faster.

Cracked Transmission Seals

Transmissions seals help keep the pressure in the transmission so the fluid can move around.  The seals are exposed to heat, and over time this can breakdown the seal and cause the fluid to leak out of the transmission.

What Are The Signs Of A Transmission Fluid Leak?

If your transmission is leaking, it’s important to repair it. The sooner you realize there is a leak, the sooner you can fix it. Sometimes small leaks and drips can be hard to notice, other times the problem is obvious there are several signs of a transmission leak. Some of them include,

  • Strange smell
  • Visible spots under the car
  • Warning light on the dashboard
  • Low levels of fluid on the dipstick
  • Odd sounds
  • Delays when shifting or when trying to move the automobile

Is It Safe To Drive A Car With A Transmission Leak?

Transmission leaks can cause your vehicle to run improperly. It is not necessarily dangerous, but it may result in damage to your car. If the car has been leaking fluid for a long time, the transmission could lock up, or go out, which could leave the car inoperable.

You could be stranded somewhere and have to pay for repairs and a tow truck. It is best to repair a leaking transmission as soon as you notice it instead of driving around with the leak and hoping nothing worse happens.

How Are Transmission Leaks Repaired?

The way a transmission leak is repaired depends on the reason for the leak. The most common cause of leaking fluid is a cracked gasket or pan. A mechanic can easily replace both of these broken parts quickly.

Some people are even capable of replacing these parts themselves. If the cause of the leak is something more serious such as a cracked or broken torque pipe, it could require more extensive repairs and may need an experienced mechanic.

How Can I Avoid Transmission Fluid Leaks?

A transmission fluid leak can be frustrating and expensive. While they can happen with almost any vehicle, there are some ways you can avoid them. Taking care of your car with proper maintenance is the best way.

Check your fluids often and adds more when needed. If you notice a change in the way your transmission is working, check for problems. Use good-quality transmission fluid in your vehicle and make sure you are using the right type for your car.