Which Transmission Cooler Line is Which

The transmission cooler lines are part of the cooling system for an automatic transmission. They are typically metal tubes that run between the radiator and the transmission, allowing coolant to flow between them in order to keep the temperature of the fluid in the transmission under control. One line is larger than the other and it is called a “return” line while its smaller counterpart is known as a “supply” line.

The return line carries used fluid back to the radiator where it can be cooled again, while supply sends fresh, coolant from there into the transmission. It’s important that these lines remain properly connected so that they can do their job correctly.

If you’re like most car owners, you may not know the difference between transmission cooler lines. Knowing which transmission cooler line is which can be important for ensuring your vehicle runs smoothly and efficiently. The two main types of lines are inlet and outlet.

The inlet line carries hot fluid from the radiator to the transmission, while the outlet line takes cooled fluid from the transmission back to the radiator. Additionally, it’s also critical that these lines stay free of any blockages or leaks as they can cause major issues with your vehicle’s performance if compromised.

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How Do You Know Which Transmission Line Goes Where?

When it comes to understanding transmission lines, it can be difficult to figure out which line goes where. Knowing the exact location of each transmission line is important in order to keep your system running smoothly and avoid any potential electrical problems. Fortunately, there are a few key factors you can use to determine exactly which line should go where.

First, you need to identify the type of power source that each line will be connected to. For example, if one of your transmissions is going from an AC generator then its likely that this particular line should go on the right side of the power grid. Additionally, look at any existing wiring diagrams or labels available with your equipment as these can provide valuable insight into which lines should connect with what part of the system.

Do Transmission Coolers Have a Flow Direction?

Yes, transmission coolers do have a specific flow direction. The cooler should be plumbed in-line with the transmission fluid line and mounted as close to the transmission as possible. The oil should enter one side of the cooler at its highest point (typically marked with an arrow or “in”) and exit on the opposite side (marked “out”).

This will ensure that all of your transmissions cooling needs are met efficiently, while also avoiding any potential problems caused by reversing the flow direction. When it comes time to replace your transmission cooler, make sure you pay attention to which way it was installed so that you can reinstall it correctly – otherwise you may experience decreased performance and even permanent damage to your vehicle’s powertrain.

What Hose Goes from the Transmission to the Radiator?

The hose connecting the transmission to the radiator is typically known as a transmission cooler line. It’s an important component for any vehicle with an automatic transmission, since it allows fluid from the transmission to flow through and be cooled off by the radiator before cycling back into the system. This helps keep temperatures in check and prevents overheating that can lead to catastrophic damage.

Transmission cooler lines are usually made from high-quality rubber or metal tubing, and should be checked regularly for signs of wear or cracking that could compromise their integrity. Additionally, they should be replaced every few years as part of standard maintenance, so make sure your car has one installed if you own an automatic!

Which Line is the Return Line on a Th350 Transmission?

The return line on a TH350 transmission is the lowest metal line that runs from the back of the transmission to the rear of the oil pan. This line carries fluid back to the transmission’s sump, and it typically has an inverted flare fitting at each end. The return line also helps regulate both temperature and pressure in order to ensure proper operation.

If this line were broken or blocked, it could cause catastrophic damage due to low lubrication levels or over-pressurization of internal components. For this reason, it is important that all TH350 owners periodically inspect their return lines for signs of leaks or blockages.

Which Transmission Cooler Line is Which

Credit: transmissioncoolerguide.com

Transmission Cooler Lines to Radiator

Transmission coolers lines are an important component in any vehicle, as they ensure the efficiency and safety of the transmission system. The lines transfer fluid from the transmission to a radiator that dissipates heat from the engine, maintaining optimal operating temperatures for both components. Overheating can lead to significant damage, so it is essential to make sure these lines are in good condition by regularly checking for kinks, leaks or other signs of wear and tear.

Can I Use Rubber Hose for Transmission Cooling Lines

Rubber hose is not suitable for transmission cooling lines because it can become brittle over time and crack, leading to a leak in the line. Additionally, rubber hose cannot tolerate high temperatures or pressures – both of which are present in transmission systems. For this reason, metal hoses specifically designed for use with transmissions should be used instead.

Which Transmission Line is the Return

The return transmission line is the conductor that runs from the load side of a circuit back to its source. It carries current back to its originating point, usually a transformer or power station. The voltage and current in this line are typically lower than those on the forward transmission line, since energy has been removed from the circuit by whatever load it is powering.


In conclusion, determining which transmission cooler line is the inlet and outlet can be tricky. However, with the right knowledge of how to identify them correctly and a few simple tools like a flashlight or screwdriver you can figure out which one is which. Now that you have learned more about each type of transmission line, you should feel confident enough to identify both of them accurately.


  • Alex Gearhart

    Alex Gearhart, an automotive expert specializing in transmissions, has over a decade of hands-on industry experience. With extensive knowledge in manual and automatic systems, Alex is passionate about educating car enthusiasts on vehicle maintenance. As the chief author at TransmissionCar.com, Alex simplifies complex concepts for readers, helping them make informed decisions about their vehicles. Outside of work, Alex enjoys road trips, restoring classic cars, and exploring new automotive technologies.

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