Trans Fluid Capacity For 5R55s Pan

The 5R55S transmission is used in several Ford vehicles, including the Explorer, Ranger, Mercury Mountaineer, and Lincoln Aviator. While the official Ford maintenance manual does not specify the fluid change interval for this transmission, some people recommend changing the fluid and filter every 30,000 miles or 30,000-50,000 km. Others suggest that the fluid does not need to be changed under normal operating conditions and can last the lifetime of the transmission. However, it is important to note that the transmission fluid level should be checked regularly, as overfilling or underfilling can lead to transmission problems.

The 5R55S transmission is used in Ford Explorers

The 5R55S transmission is known to have some issues, with many reports of failures due to worn-out servo pin bores, which can cause slipping in second and fifth gears and damage to the overdrive band. Other common problems include strut anchor breaks and solenoid pack failure. As such, regular maintenance is crucial to prevent these issues and extend the life of the transmission.

One important aspect of maintenance is regularly changing the transmission fluid. However, this can be tricky due to the sealed transmission design, which lacks a dipstick. To change the fluid, you need to remove the drain plug and carefully balance the pan to avoid spilling. It is recommended to replace around five quarts of fluid, and Mercon V synthetic fluid is the recommended type for this transmission.

When it comes to repairs or rebuilds, it is generally advised to have a professional handle the job, as the 5R55S is not a beginner-friendly transmission. The cost of a rebuild can vary, but it typically ranges from $1400 to $3000, depending on whether you go to a shop or do it yourself.

Upgrades and modifications are also available for the 5R55S transmission. For example, installing bronze sleeves for the servos can help address the issue of worn-out servo pin bores. Additionally, adding a transmission cooler can help prevent heat-related damage, which is a common cause of transmission failure.

The transmission holds 12 quarts of fluid

It is important to note that the 7/8” drain plug should not be removed. Once an assistant starts the vehicle in Park, check if fluid comes out of the hole. If no fluid comes out, more fluid needs to be added. If fluid does come out, allow it to drain until it comes to a drip, indicating that the fluid level is correct. Reinstall the T30 torx plug and proceed to the drive cycle test.

Alternatively, some people choose to perform a transmission flush. However, this method has been criticised by some mechanics, who claim that it can damage the transmission. They recommend dropping the pan and changing the filter and a portion of the fluid every 30,000 miles instead. This method typically involves removing the outer part of the two-part drain plug to drain some fluid, then removing the pan bolts and carefully dropping the pan. After cleaning the pan and installing a new filter, the pan can be reinstalled, and new fluid can be pumped in through the drain plug.

A flush is not recommended for the 5R55S transmission

The 5R55S transmission is a type of automatic transmission found in some Ford vehicles. While it may be tempting to perform a transmission flush on this system, it is generally not recommended by automotive experts and mechanics. Here are several reasons why a flush is not the best option for the 5R55S transmission:

Potential Damage to the Transmission

Some sources strongly advise against transmission flushes, claiming that they can cause significant damage to the 5R55S transmission. One mechanic even refers to it as a "huge scam that destroys transmissions." The exact cause of this damage is not specified, but it is presumed to be due to the transmission's unique design and the potential for human error during the flush procedure.

Inadequate Fluid Replacement

The 5R55S transmission is designed to hold approximately 13 quarts of fluid. However, a flush does not actually replace all of the fluid. Instead, it only mixes the new fluid with the old, resulting in a diluted solution that may not provide optimal performance or protection for the transmission.

Contamination and Pressure Issues

During a flush, the machine stirs up and pumps the transmission fluid, potentially dislodging dirt and debris that could then be circulated throughout the transmission. Additionally, there may be pressure issues with the flush machine, further complicating the process and potentially causing harm.

Recommended Alternative: Drop the Pan

Instead of performing a flush, it is generally recommended to drop the pan and replace the transmission filter. This method allows for a more controlled fluid replacement, ensuring that only clean fluid is introduced into the system. By dropping the pan, you can directly access the filter and replace approximately 6 out of the 13 quarts of fluid. This approach is supported by mechanics and DIY enthusiasts alike, who believe it is a safer and more effective way to service the 5R55S transmission.

In summary, while a transmission flush may seem like a convenient option, it is not recommended for the 5R55S transmission due to the potential risks involved. The preferred approach is to drop the pan, replace the filter, and manually replace a portion of the fluid. This method helps ensure the transmission's longevity and optimal performance.

The transmission fluid should be changed every 30,000 miles

It's important to refer to the owner's manual for specific guidelines, as some vehicles have unique requirements. Additionally, driving habits can also influence the frequency of transmission fluid changes. If you frequently tow, haul heavy loads, or drive in stop-and-go traffic, your transmission fluid may need to be changed more often, even if you haven't reached the recommended mileage interval.

The transmission fluid plays a crucial role in lubricating the moving parts of your transmission and facilitating smooth gear shifts. Over time, the fluid can break down due to heat and contamination, leading to poor performance and potential transmission damage. Regular fluid changes help maintain optimal transmission performance and prevent costly repairs in the long run.

When checking the transmission fluid, pay attention to its colour and consistency. Fresh fluid is typically bright red, while dark brown or blackened fluid may indicate contamination or degradation. Additionally, metallic flecks or debris in the fluid can suggest excessive wear or damage to the transmission components.

It's worth noting that simply changing the fluid may not be sufficient for optimal maintenance. In some cases, you may need to drop the pan, replace the filter, and only change a portion of the fluid. This is because not all of the fluid can be drained, as some of it remains in the torque converter and internal passages. Therefore, a complete fluid change might require multiple drain-and-fill cycles.

Some vehicles might also offer a flush service instead of a standard fluid change. However, this is a controversial topic, as some experts believe that flushing can dislodge debris and clog internal passages or blow out old seals. Therefore, it is generally recommended to avoid flushing and stick to the standard fluid change procedure as per the vehicle manufacturer's recommendations.

Mercon V is the recommended fluid for the 5R55S transmission

The 5R55S transmission normally requires 5-6 quarts of Mercon V for maintenance drain/refill. If you are just draining the pan, you will need to replace around 5 quarts of fluid.

It is important to note that overfilling the transmission with Mercon V can cause damage and lead to leaks.

When refilling the transmission, you will need to raise the vehicle with a floor jack and place jack stands under the vehicle's recommended jacking points. Lower the vehicle as close to level as possible. Place an oil catch container under the drain plug and remove it with a 7/8 wrench to allow the fluid to drain.

For an empty pan, you will then need to reinstall the drain plug and gasket, and tighten to 19 ft. lbs. with a 7/8 socket. Remove the small level-indicating plug using a T-30 Torx bit socket and install a transmission fluid fill adapter. Add 2-3 quarts of Mercon V to the pan and start the vehicle, adding an additional 2 quarts.

Allow the vehicle to run until the transmission temperature reaches 27-49°C (80-120°F), which should take around 10-15 minutes. Slowly cycle through each gear, allowing the fluid to fill each valve and engage while holding the brake pedal fully depressed.

Place the vehicle in neutral and check the transmission fluid level. If no fluid drains back, more fluid will need to be added in increments of 1 pint. Allow the fluid to drain to the correct level, which is when it comes out as a thin stream or drip. Remove the special filler adapter and reinstall the leveling plug, torquing to 89 inch-lbs.

Turn off the engine and lower the vehicle back to the ground.

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