Most car owners who drive vehicles with an automatic transmission understand the vital role that this part plays in the vehicle’s overall function, even if they don’t know exactly how and why it works. Transmission repairs tend to be some of the more costly maintenance work car owners encounter, but they are far less expensive when the problem is caught before a major failure. The key is understanding how and why transmissions leak, and also how to diagnose a transmission fluid leak.
Identifying the Fluid
If you have never seen transmission fluid before, it is a bright red substance that runs a bit thinner than engine oil but a bit thicker than brake fluid (in general). It acts as a multipurpose lubricant and hydraulic solution, and it’s also designed to condition seals and gaskets so they last longer.
Finding a Leak
Some vehicles still have ways of assessing the transmission fluid level in the system, but many more recent models have been designed with closed systems. Either way, there is a simple diagnostic confirmation that will tell you if your vehicle is leaking transmission fluid. You just have to check for stains underneath. Find someplace clean and level, so your vehicle and engine rest naturally and you don’t have to worry about other fluids or previous stains interfering. Then follow these steps:
- 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.
Leaks are often at the sites of gaskets and seals, which means that they might not be apparent while the level of fluid in the pan is low. After the car stops, lubricating fluid drains out of components and back to the pan, just as it does with engine oil. As the pan level rises and other parts near the bottom of your transmission also get coated in fluid from the pan’s reservoir, previously unseen leaks can appear.
Diagnosis: Positive
If you find leaks of a bright red fluid, it likely confirms the diagnosis of a transmission fluid leak. Some manufacturers will use transmission fluid in power steering systems as well, so once you find a leak, you should talk to a certified technician about identifying its exact source and enacting a repair. The sooner you do, the easier it is to contain any issues.
FAQs
If you find leaks of a bright red fluid, it likely confirms the diagnosis of a transmission fluid leak. Some manufacturers will use transmission fluid in power steering systems as well, so once you find a leak, you should talk to a certified technician about identifying its exact source and enacting a repair.
How to detect transmission fluid leak? ›
Be on the lookout for reddish-brown stains on your garage floor or driveway. Many times, this is your first sign that there is an issue with the level of your transmission fluid. These spots can be in the center of the vehicle (RWD) or on the side of the vehicle where the transmission is located (FWD).
How do you pinpoint a transmission leak? ›
To identify a transmission fluid leak, be vigilant for any puddles of fluid under your car and be aware of any burning odors. Inspect the cooling lines, gaskets, and seals for signs of damage. If the leak is minor, you may attempt to repair it yourself, but if it's major, it's best to seek professional assistance.
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.
Does blue devil transmission sealer work? ›
Most did nothing. This product did not completely stop the leak but helped to limit it to a few drops under the car, I do not have to fill it with fluid nearly as often or clean up the leak in the driveway. Keeps the trans under control, shifting is good. Very satisfied customer.
Where would a transmission leak be located? ›
Although there are multiple places on a vehicle where transmission fluid can leak, the 3 most common include: Pan gasket. Cooler lines. Output, tail, or torque converter seal.
What can fix a transmission leak? ›
In case the problem is a transmission leak, a simple reseal service, and transmission fluid flush is all you need to fix the problem. However, if your transmission is severely damaged, you'll probably need a replacement transmission for your car.
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.
What does a puddle of transmission fluid look like? ›
You know what that red (maybe green or blue) puddle means: it's a transmission leak. If your vehicle is running OK, and you have no major complaints, it may be tempting to shrug it off. While that may be a natural response, it's not the recommended one.
What should be the first step when diagnosing a fluid leak? ›
There are a few valuable steps to take that will get you started on your fluid leak diagnostic. First, take a look at the color of the fluid. If it's clear or light-colored, it's probably just water from your car's air conditioning system or exhaust system.
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.
What color is transmission oil when it leaks? ›
Red Fluid Leaking from Car
If you notice your vehicle leaking red fluid, this is the transmission. This red color helps easily identify the problem, but sometimes, it takes more than the color to know about a transmission leak. Other signs to be aware of include: Odor: Transmission fluid usually smells like petroleum.
Is a transmission leak expensive to fix? ›
How Much do Transmission Leaks Cost to Repair? The cost to fix a transmission fluid leak in a vehicle can be as little as $150 to replace a seal and around $1,000 to for a new torque converter.
Can transmission fluid leak from a 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 much does it cost to diagnose a transmission leak? ›
The average cost for a Transmission Leak Inspection is between $44 and $56. Labor costs are estimated between $44 and $56. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.
Can you drive with transmission fluid leaking? ›
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.
