Every car has a transmission built-in next to its engine. Whether you have a manual transmission car or you are driving an automatic transmission, it is important that you know how to diagnose, repair and maintain this important component of your car.
Why? Because your car simply won’t run without it! So in this blog post, I will discuss a very common issue with transmissions – fluid leak.
Read on and learn how to diagnose your car if it is already leaking transmission fluid all over your garage!
First Up, What does Your Transmission Do?
The main power of your car comes from its engine, and what the transmission do is to transfer that power to your car’s four wheels and ensure they have enough power to run the car at a certain speed.
To accommodate the power for faster speed, transmissions have gears. Shifting to higher gear changes the amount of power transferred to the wheels, which enables you to achieve speed using the high gear.
Failure to change gear when your car is in motion will result to engine hitching or pulling as you try to move forward or accelerate. Overtime, the transmission components and gaskets worn out, causing fluid leaks especially if maintenance is neglected.
How and Where to Spot Transmission Leaks?
To be able to diagnose correctly if you have transmission fluid leak, you need to identify if your fluid level is low. Sometimes, a visible fluid leaking under your car isn’t noticeable, so you need to always check the dipstick of your transmission.
Now you can’t get the real level of your fluid if your engine isn’t in the optimal operating temperature. So better drive your car for about 15 minutes and see to it that your engine has reached at least 85 degrees Celsius.
After that, you may now check your fluid level using your transmission’s dipstick. Take note that your car must be in a level surface to get accurate reading. If your fluid level is low compared to your previous check, then it is highly likely that your transmission is leaking somewhere.
The first thing to look at is under your car. Check if there are visible fluid underneath the transmission and engine area. The most obvious way to confirm if the fluid is from the transmission is by its color.
- Reddish or pinkish color (fresh and usable fluid)
- Brownish color (needs repleacement)
- Darkish color that smells burnt (burned transmission fluid)
Whatever color you see inside your engine bay or underneath your car that comes with the aforementioned colors, it is from your transmission.
Now that you confirmed that you have transmission leak, it is time to find out where that leak is coming from. The first spot to look for is your radiator.
Radiators especially those designed for automatic transmission, have special cooling lines (or pipes) for transmission fluid. Yes, radiator doesn’t just help in lowering your engine’s temperature but also your transmission as well.
So check your radiator closely especially the transmission pipes that connects to the radiator. If you see some minor fluid leaking, then you may need to replace the clamp or the hose itself.
If you are using aftermarket transmission coolers which are commonly installed before or after the radiator, check the hoses and clamps connection as leaks may also occur on those areas.
The next area that you should look at is your power steering fluid components. If you don’t know yet, both power steering and transmission uses the same fluid which is hydraulic type of fluid.
So it is wise to check your power steering section in your engine bay to ensure that they don’t have leaks.
First you need to check the hoses that are connected to your power steering reservoir. Basically it has two hoses, one inlet and the other is the outlet hose. Both can be a source of leak especially if the clamps or hoses are worn out already.
You may also want to check the other end of the hose which is connected to your power steering pump. Check if the steering pump leaks fluid including its gaskets and hoses. If all is good, then you need to go to the next possible leaking spot.
The next spot is underneath your car, so go underneath your car and look for your transmission fluid pan. Check your fluid pan and see if the leaks are coming from the sides where there is a sealing gasket. If you there’s a visible leak or you felt the oil on your fingers, then you have transmission pan leaks.
Most of the time, transmission leaks are found in this area due to the gasket getting worn out fast. This is due to the abuse that the transmission gets when you drive your car for long hours, which increases the temperature of the fluid.
If this is the case, you need to unbolt and remove the transmission pan, remove the old gasket and use a new one to get better seal. As an alternative, you can also use a high heat resistance silicon gasket maker as your transmission pan gasket.
If you can’t see any leaks from your transmission pan, look somewhere else near the pan. Most transmissions have cooling lines beside or above the transmission pan. See if they also have leaks. If they do, then you have to replace oil seals or gaskets to solve any transmission leak issue.
Next spot to check is your transmission’s bell housing.
Bell housing is where most of the transmission fluid is situated. It also houses the torque converter, which is responsible for using fluid to transmit power to the transmission, hence preventing the engine from stalling.
Now your car’s bell housing is directly connected to the engine and has an input seal. This connection is of course sealed using a gasket to prevent any leaks. Check the entire connection if the leak is coming from this area.
If there are no leaks on the surrounding area of your vehicle’s bell housing, turn your attention to the gear selector and inhibitor switch. Sometimes, fluid leaks comes from this area as well.
If your vehicle is a truck or SUV, especially if equipped with 4×4 system, you might want to look for leaks in between the tail shaft and the transfer case.
Transmission fluid also leak in both of these areas especially the transfer case. Once the transmission fluid pump initiates, it puts a lot of pressure inside the transfer case. If the sealants and gaskets are worn out, expect leaks to be present at these areas.
The tail shaft leads to your rear drive shaft. You need to check the seals of this shaft to ensure that they are leak-free.
Conclusion
I hope you learned a lot from this short post on how to diagnose and check transmission fluid leaks. So if you have any issues with your car leaking transmission fluid, then just do check the areas that I mentioned above.
To understand more about this matter, you may want to watch my video below and learn how to check for transmission leaks. The video is in Tagalog but has English subtitle. Enjoy!
