2012-2019 Subaru Legacy Outback TR690 Transmission Fluid and Filter Change How To DIY

Summary

This DIY guide walks you through the process of changing the transmission fluid on a Subaru. It covers everything from lifting the vehicle, draining the old fluid, and removing the transmission pan, to replacing the filter and cleaning the pan. Detailed instructions are provided for applying RTV to reseal the pan, filling the transmission with new fluid, and checking the fluid level using a dipstick-like method. The guide emphasizes safety and precision, ensuring a proper fluid change for a smoother driving experience.

Takeaways

• 😀 Jack up the vehicle to a height that allows you to slip under and keep it relatively level for ease of work.
• 😀 Use jack stands in the rear and roll-up stands in the front to achieve a stable setup while working under the vehicle.
• 😀 Locate the transmission drain plug on the passenger side of the transmission pan, and use an 8mm Allen wrench to remove it.
• 😀 Allow the fluid to drain completely, then snug the drain plug back in, torquing it later for a proper seal.
• 😀 Remove the perimeter bolts using a 10mm socket and carefully unstick the transmission pan from the RTV seal, using a putty knife or flat screwdriver.
• 😀 Slowly peel away the pan, ensuring you have a catch pan ready to catch any fluid drips. Secure the pan with one bolt to prevent it from falling.
• 😀 After removing the pan, take out the transmission filter by unbolting three 10mm bolts. Ensure the O-ring stays attached or remove it from the filter location.
• 😀 Clean the sealing surface thoroughly using a razor blade and brake cleaner to remove old RTV and oil, ensuring a smooth, debris-free surface for reinstallation.
• 😀 Apply fresh transmission fluid to the new filter's O-ring before installing it, and tighten the three bolts to the proper torque.
• 😀 Clean the magnet in the pan and remove any debris before reinstalling it. Make sure to clean the pan interior thoroughly before reusing it.
• 😀 Apply a thin bead of RTV around the perimeter of the pan, ensuring to circle the bolt holes. Allow the RTV to cure for about an hour before torquing the bolts to 3.7 ft-lbs or 44 in-lbs.
• 😀 Refill the transmission fluid through the fill plug, using a hand pump to gradually fill the transmission until fluid begins trickling out of the fill plug.
• 😀 Monitor the transmission temperature (between 95-113°F) while running the vehicle through the gears. Adjust the fluid level as necessary until it drips out of the fill plug.
• 😀 Once the fluid level is correct, torque the fill plug to 37 ft-lbs, clean up any fluid drips, and the job is complete.

Q & A

Why is it important to jack up the vehicle as high as possible before starting the transmission fluid change?

Jacking up the vehicle as high as possible ensures that you have enough clearance to slip under the vehicle easily. It also helps in leveling the vehicle, which is important for accurate fluid drainage and ensuring a proper seal when reinstalling the transmission pan.

What tool is used to drain the transmission fluid, and where is it located?

An 8mm Allen wrench is used to drain the transmission fluid. The drain plug is located on the passenger side of the transmission pan.

How do you deal with the sticky RTV when removing the transmission pan?

To remove the sticky RTV from the transmission pan, a 2-inch putty knife is recommended. If unavailable, a flat screwdriver can be used to gently tap into the seam and slowly peel the pan away, ensuring that the fluid doesn't drip excessively.

Why is it important to clean the transmission pan thoroughly before reinstallation?

It's crucial to clean the transmission pan thoroughly to remove any leftover debris, old RTV, and oil. Any leftover contaminants can cause issues with the new gasket's seal, leading to leaks or other transmission problems.

What is the correct procedure for installing a new transmission filter?

After cleaning the surface, a new transmission filter is installed by first ensuring the O-ring is attached and lubricating the filter with a small amount of transmission fluid. The filter is then bolted into place with three 10mm bolts.

How do you handle the RTV gasket during reinstallation?

When reinstalling the pan, apply a light bead of RTV gasket maker around the perimeter and bolt holes. The RTV should be about 1/16 to 1/8 inch thick, ensuring a uniform seal. Follow the manufacturer’s instructions on the RTV bottle for optimal results.

How should the transmission pan be tightened?

The transmission pan bolts should be tightened in a criss-cross pattern until the RTV begins to squish. Typically, the torque specification is 3.7 ft-lb or 44 in-lb, but this may vary depending on the specific model and RTV instructions.

How do you check if the transmission fluid level is correct after refilling?

After filling the transmission, run the vehicle through the gears while monitoring the fluid temperature. Once the temperature reaches between 95 and 113°F, check the fluid level by removing the fill plug and checking the fluid level using a small pick or similar tool.

How do you know when to stop adding transmission fluid?

You should stop adding transmission fluid once it starts trickling out of the fill plug. This indicates that the transmission is full. The fluid level should be at the edge of the fill plug's rim when checked with a pick.

What is the final step after confirming the transmission fluid level is correct?

After confirming the correct fluid level, torque the fill plug to 37 ft-lb (or the specified torque value) and clean off any excess fluid around the fill plug area to complete the job.