Unleash the Beast: 4EAT Performance Transmission Rebuild

2004 Subaru Forester 4EAT Performance Transmission Build

This video demonstrates a performance transmission rebuild of a 4EAT, found in the 1997 to 2012 Forester, WRX, Impreza, Legacy and other Subaru vehicles.

This particular video is of a 2004 Subaru Forester automatic that was sent to us for our 4EAT transmission upgrade.

Teardown of this transmission: https://youtu.be/TFORrB4SowM
4EAT Valve Body Rebuild: https://youtu.be/L5LwuQ7WUjU

The transmission fluid is pretty gross- 20 years without a flush or service!

The 4EAT was at our shop for a complete performance transmission build, including our extra clutch set up, our upgraded performance modified valve body and of course, it's going to also get a high stall torque converter.

The high stall torque converter makes a night and day difference in the performance and acceleration of these vehicles, it almost makes it feel as if you put a second engine under the hood and causes no undesirable effects as far as streetability is concerned.

IPT Performance Transmissions specializes in Subaru high performance automatics and Subaru built autos, as well as performance rebuild kits, modified valve body and high stall torque converters. IPT is recognized as the leader in 4EAT transmission technology and has been upgrading the performance of the 4EAT since opening in 2001.

If you own or work on an automatic transmission equipped Subaru or have one that's got transmission problems, be sure to watch this video to learn about the 4EAT auto gearbox and how to avoid some of the common problems. If you're experiencing any transmission problems or need an upgrade to handle additional torque and horsepower, be sure to contact our experts at IPT Performance Transmissions for a free consultation!

More details on our products can be found here:
https://www.importperformancetrans.com/

Subaru High Performance Automatic Transmission Parts:
https://www.importperformancetrans.com/index.php?l=product_list&c=60

Tool: Subaru Pinion Nut Tool 499987003

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This transmission incorporates a lock-up torque converter, engaging in all forward gears except 1st, and it's available in both FWD and Full Time AWD setups.
Since its inception, the 4EAT transmission has undergone continuous development and refinement, with various Subaru models witnessing changes, including a significant redesign in 1997.

This redesign eliminated the 2-4 band, revamped internal components, and introduced a new electronic control system. The second design is easily recognisable by the lack of a band adjusting screw and the addition of a spin on oil filter, which was eliminted in 2008.

For a comprehensive understanding of specific 4EAT operational traits and features, consult the relevant Subaru service manual for the specific year and model you are working on.

Some 4EAT's are also equipped with the VTD (Variable Torque Distribution) AWD system. This AWD system adjusts power to wheels depending on driving conditions. Typical biasing is 45% to the front wheels and 55% to the rear wheels.

Gear ratios are as follows:
Automatic transmission gear ratios:
1st - 2.785
2nd - 1.545
3rd - 1.000
4th - 0.694
reverse - 2.272
final drive ratios (application dependent) - 3.73, 4.11. 4.33