If you spot a small puddle of dark reddish fluid beneath your vehicle, this isn't a good sign, as it mainly indicates a transmission fluid leak. It can stain your garage or driveway, and most importantly, it can be costly to repair and replace the fluid. Transmission fluid leaks are easy to remedy. However, you must know what caused the leak to fix the issue appropriately.
If you can't determine the cause, the Montgomery Chrysler Dodge Jeep Ram (CDJR) team can help point you in the right direction. You can also schedule maintenance and repair services, and we'll be happy to repair your transmission fluid leak at an affordable price. Below are the main reasons your transmission fluid leaks when your car is parked.
Faulty Transmission Pan or Gasket
The fuel pan gasket is the number one culprit if your vehicle's transmission fluid leaks when your car is parked. Cars with automatic transmissions have a pan gasket designed to catch most fluids leaking from the engine. Over time, loose bolts or holes may occur, causing the transmission fluid in your parked car to leak. Sometimes impact can also damage the pan if a sharp object hits it.
When the seal between the transmission and pan deteriorates over time, it can corrode, crack, wear out or even dissolve after a while. When this happens, your vehicle transmission fluid may leak when parked.
The best way to prevent this problem is to inspect the pan and gasket position. The best time to do this is when performing the fluid change. Check for rust that can damage the pan and create holes. Tightening loose bolts can fix the issue if there's no other damage. If you suspect the pan is damaged, you may need to replace it.
Bent Transmission Pan
If someone tries to replace the transmission fluid and uses too much force to remove the sealant, the extra force used can cause the pan to bend. Transmission pans made of steel aren't strong and durable enough, and they can bend easily. When it bends, the pan can't create a seal around it, and transmission fluid can escape through the gaps and cause a leak.
Leaking Transmission Drain Plug
Another fault that can result from using too much force when changing the transmission fluid is damage to the drain plug. The repair professional must tighten the drain plug according to factory specifications. Too loose or too tight can cause transmission fluid to leak.
There's an O-ring used to seal the plug. It'd be best if you replaced this seal every time you replaced the transmission fluid. This is because it tends to have a similar lifespan as the transmission fluid. If re-used, it'll wear off and create an opening that leads to a transmission fluid leak.
Damaged Fluid Lines
If you notice the transmission fluid leak happens toward the front of the vehicle when it's parked, it could be an issue with the transmission line. Most vehicles have fluid lines that run to the transmission cooler in front of the car. Most of these lines are designed to last many years as they're made of steel or aluminum. However, they may crack or break at any time and eventually cause a leak. The leaking transmission fluid lines may also be caused by the absence of protective coating on the line.
Damaged Seals
An automatic transmission contains seals designed to keep the fluid in place and prevent the fluid from leaking. However, these seals deteriorate over time and develop cracks that lead to leaks. The most commonly affected seals often lead to leaks at the input and output shaft seals.
These critical seals sit where the torque converter connects to the transmission and where the transmission connects to the wheels. Different temperatures, such as heat and cold, can affect seal conditions, causing them to degrade or warp and ultimately cause a leak. Other places to check include the tail housing, shifter housing, and speedometer input seal.
Dirty Transmission Fluid
Like engine oil, transmission fluid can be subject to dirt and debris buildup over time. If ignored, the transmission lines can become clogged, and the excess pressure can cause the pipes to burst or crack, causing a leak.
When you delay changing the fluid, the transmission fluid tends to break down and cause seals to wear more quickly. The delay eventually causes the fluid to leak when the vehicle is parked. The general best practice for maintaining a healthy car is routine maintenance, such as an oil change every three months, depending on your driving habits.
Torque Converter Leak
The torque converter has the critical function of propelling the transmission fluid into the vehicle's power system. It's a donut-shaped coupling that sits between the transmission and the engine. The transmission fluid acts as a lubricant for moving parts in the torque converter and works like the hydraulic fluid to propel the turbine.
The transmission fluid will likely leak if the coupling gets a small crack or suffers any damage. If a damaged converter causes your transmission fluid to leak, you may want to call a professional to replace it.
Overheated Transmission
If the transmission fluid only leaks when the vehicle is parked, it's a sign of overheating. The transmission includes several seals to keep the fluid from leaking, and many of them are likely to fail if you have been driving the whole day with heavy acceleration or high speed, especially in hot weather. When the fluid overheats, it may require extra sealing to keep the fluid from leaking. If not, the seals may loosen and cause the transmission fluid to leak.
Remember to stay up to date with routine maintenance and schedule regular transmission fluid changes to keep your vehicle operating correctly and prevent leaks. If your vehicle leaks transmission fluid when parked, trust that the experts at Montgomery CDJR can help fix the problem. If you're near Nicholasville, Kentucky, you can visit us or call to book a service appointment. Also, call us if you need help discovering what's causing the transmission fluid in your vehicle to leak.
Shimano Alfine 8 Speed Internal Gear Hub (IGH) soaking in oil bath (auto transmission fluid - ATF) by Robert Thomson is licensed with CC BY-SA 2.0
FAQs
If the transmission pan or seal becomes damaged or worn out, it can lead to fluid leaks. There are seals throughout your vehicle to keep fluids where they're supposed to go. If those seals deteriorate, leaks can occur. This can happen if your engine is overheating or has been run for too long in very hot weather.
Why is my transmission fluid leaking when parked? ›
If the transmission pan or seal becomes damaged or worn out, it can lead to fluid leaks. There are seals throughout your vehicle to keep fluids where they're supposed to go. If those seals deteriorate, leaks can occur. This can happen if your engine is overheating or has been run for too long in very hot weather.
What is the most common reason for transmission fluid leak? ›
Causes of Transmission Fluid Leaks
Over time, road debris and heat can cause the transmission fluid lines to crack or break, which can cause fluid to leak out. Another reason for lost fluid is your vehicle's torque pump has become cracked or an axle seal has been compromised.
Can a torque converter leak transmission fluid? ›
The torque converter pushes the transmission oil throughout the transmission. It's basically a pump, and if this pump develops a crack, you'll end up with a transmission leak. The needle bearings inside the torque converter can also get damaged and this, too, will cause a transmission fluid leak under your car.
How do I find out where my transmission fluid is leaking from? ›
Finding a Leak
- Lay out a clean drop cloth underneath the vehicle's parking space.
- Park on top of it, centering the cloth as much as possible and making sure the entire engine block and transmission are over it.
- Leave the vehicle off and parked overnight.
- Check the cloth for stains.
Usually, leaking water is simply condensation from the aircon unit – surprisingly common during summer – or the exhaust, which is more common in winter. Another typical cause is your windscreen washers, but again this is unlikely to be a major issue and you can probably just ignore it.
What are the symptoms of a bad torque converter? ›
It's important to note that symptoms of bad torque converter can vary depending on vehicle model. Symptoms can range from transmission slipping, shuddering during acceleration, rough idling, shaking in certain gear, unusual noises, delayed or rough shifting, and even complete transmission or torque converter failure.
Where else can a transmission leak from? ›
Cooler Lines
The cooler lines can allow wear down and break over time due to heat exposure and debris. If a cooler line cracks, a leak will occur as transmission fluid is circulated through the system.
Where is the most likely area for a transmission to leak? ›
The most common source of a transmission leak due to faulty installation is from the transmission pan. The pan is not mounted correctly or incorrect bolts are used to secure it. Something as simple as these bolts will make transmission fluid leak from the pan. Hopefully, the bolts just need to be tightened.
Where do automatic transmission oil leaks commonly occur? ›
Damaged Seals
An automatic transmission contains seals designed to keep the fluid in place and prevent the fluid from leaking. However, these seals deteriorate over time and develop cracks that lead to leaks. The most commonly affected seals often lead to leaks at the input and output shaft seals.
If you find transmission fluid leaking from the bell housing area between the engine and automatic transmission, you're probably dealing with a bad front pump seal (also known as a torque converter seal). The seal, which is usually located in the transmission pump, fits over the snout of the torque converter.
How do you test a torque converter for leaks? ›
Torque converters must be tested to be oil-tight to avoid wear of the internal parts and early failure. The part is placed in a simple chamber in an adapter of the leak testing system which seals all openings. Then the part is evacuated and the evacuation pressure is held for about 2 sec to check for gross leaks.
Can a sealed transmission leak? ›
Transmission Seals
Over time, heat and lack of fluid maintenance causes wear and tear on the seals in the transmission system, causing damage that creates a fluid leak.
Does transmission fluid leak when parked? ›
Damaged fluid lines are another common reason transmission fluid leaks when a car is parked. The lines carry the transmission fluid to the cooler, and even though they can withstand everyday use, they can crack or break over time. If this happens, it can be an expensive repair.
Can transmission fluid leak from dipstick? ›
My dipstick tube had been misaligned for a few months, which caused it to rub against the axle slightly. By the time I noticed it. the tube had been worn just enough to be weakened, and was weeping a very slight amount of transmission fluid.
How to stop transmission fluid from leaking? ›
All you'll need to do is purchase a new gasket (which is relatively inexpensive). Also, make sure the bolts in the pan are tightened enough. If they're not, this could result in a leak. Many times the pan isn't secured properly after a transmission fluid change, causing a transmission leak to occur.
Does transmission fluid leak when the car is off? ›
Faulty Transmission Pan or Gasket
The fuel pan gasket is the number one culprit if your vehicle's transmission fluid leaks when your car is parked. Cars with automatic transmissions have a pan gasket designed to catch most fluids leaking from the engine.
Can a transmission stop leaking on its own? ›
A transmission leak will not get better on its own. If it goes unchecked, vehicle operation will eventually be affected, and you may find yourself with an expensive repair. So, while it may be safe to drive with a leaking transmission, it's not advisable, and you shouldn't put off fixing the problem.
How do you know if your transmission seal is bad? ›
You can tell if your transmission is leaking if you notice any of the following signs:
- The level is “low” on the dipstick.
- Gear slippage while accelerating (feels like a hesitation or brief loss of power)
- The dashboard warning light has come on.
- Dark spots on the driveway (usually pink or red)
The fuel pan gasket is the number one culprit if your vehicle's transmission fluid leaks when your car is parked. Cars with automatic transmissions have a pan gasket designed to catch most fluids leaking from the engine. Over time, loose bolts or holes may occur, causing the transmission fluid in your parked car to leak. Sometimes impact can also damage the pan if a sharp object hits it.