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Automatic transmissions typically reach 150,000 miles without much issue; some even surpass 300,000 miles. However, if this vital component starts overheating, its longevity may be cut short.
There are many possible causes of overheating, including problems with your transmission cooler lines (also referred to as cooler hoses or transmission tubing). These help maintain safe temperatures by sending hot fluid from the transmission to a cooler and then back.
If your cooler lines start having issues, such as leaks, blockages, or wear and tear, it can impact the efficiency of the cooling process, leading to overheating.
Thankfully, JEGS is here with an in-depth transmission cooler hose guide covering everything you need to know to resolve any issues and get back on the road.
We'll start by reviewing how cooler lines work and the importance of transmission fluid. Then, we'll explore the different parts of this system. Finally, we’ll share how to choose the best hoses and securing hardware for your needs.
Let's get started.
The cooling line system in an automatic transmission ensures temperatures stay within a safe operating range, typically between 175°F and 200°F.
This system works by circulating hot automatic transmission fluid (ATF) from the transmission to the radiator for cooling and then returning. The cooler lines consist of both "hot" and "cold" lines. The hot line carries the heated ATF to the radiator, while the cold line returns the cooled fluid back to the transmission.
Without this constant ATF flow, overheating may occur, typically at temperatures of 270°F or more. Overheating can cause issues like warped components, degraded fluid, and damaged seals, potentially leading to costly repairs or complete transmission failure.
Transmission fluid helps your automatic transmission run smoothly by acting as a lubricant for its moving parts, reducing friction and wear.
More importantly, ATF acts as a coolant, helping to regulate the temperature within the transmission system. As the vehicle operates, the transmission generates heat. This heat is absorbed by the transmission fluid, which is then circulated through the cooler lines to the radiator, where it is cooled and then returned to start anew.
Maintaining your ATF's quality and level is vital to prevent increased friction and overheating. Thankfully, regular fluid checks and changes (recommended every 30,000 to 60,000 miles in many cases) can help preserve the lubricating and cooling properties of your ATF.
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Now that you have a better understanding of how this system works, let’s look closer at the various cooler line and hose components:
When selecting the right hose for your transmission cooler lines, consider the type of transmission, the transmission cooling line configuration, and your vehicle's specific requirements.
For vehicles with pre-bent metal lines, OEM replacement lines are recommended for a proper fit and optimal performance. These are vehicle-specific, ensuring easy installation and reliable operation.
Rubber lines are a cost-effective choice for temporary fixes or custom installations but should be kept away from hot components like exhaust systems and engine parts to prevent damage.
Braided lines, such as nylon or stainless steel, are suited for performance applications like towing a heavy load or enjoying a day at the track, offering enhanced durability and abrasion resistance.
For high-performance vehicles, you can also consider AN fittings coupled with PTFE (Polytetrafluoroethylene) hoses, which offer superior chemical resistance and high-temperature tolerance.
When using AN fittings, ensure the correct adapter is used, especially with aluminum transmission cases, to avoid the risk of splitting due to improper fitting.
Select the right hose based on factors like durability, heat resistance, flexibility, and cost, and ensure you choose appropriate fittings and clamps for a secure, leak-free connection.
Whether you need OEM replacement lines, rubber hoses for temporary fixes or custom projects, or braided or PTFE lines for performance applications, JEGS has you covered.
With a wide range of transmission cooler lines, fittings, and hose clamps, JEGS provides high-quality products to meet your automotive needs.
Still have questions? Contact our team today.
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