Transmission oil change for Subaru WRX/STi:

This is a guide on how to change your transmission oil in your turbo Subaru. Transmission oil is usually changed at 30,000 mile intervals, though more frequent changes are suggested if you take part in track days.

Transmission oil:

Subaru 75W90 Extra-S Gear & Transmission Fluid – 1 Quart Bottle

Subaru 803916080 Manual Transmission Drain Plug Washer

Tools needed:

21mm Socket wrench or other tool of your choice
(I used a socket set with the large spark plug fitting and hollow
extension for extra leverage, dad’s tent is now missing one pole.)
– New sump washer
– Funnel
– 2 foot length of garden hose or similar sized tubing.
– Gear oil* – 3.9 quarts for wrx/sti gearbox/front diff. (Extra 800ml for rear diff)
– Oilpan or large container capable of holding 4+ quarts.

1.) First things first, jack the car up, or drive it onto wheel stands. Make sure the hand brake is on. T
Do not go under the car unless you’re sure it’s secure on it’s stands.

2.) Ensure the car is cool enough to work on, wait at least an hour after driving. Now you’ll need to find the transmission dipstick, which is located between
the turbo and intercooler. Pull it out.

3.) Now you can crawl under the car with your socket, dropsheet & oil pan. Looking from the middle of the car towards the front, you’ll be able to
see the drive shafts, transmission & diff, transmission plug, the engine oil sump plug.

4.) The front transmission oil plug is the one you want, loosen it and then slowly unwind it by hand until the end of the thread, then get yourself and the cat out of the way before you both get covered in oil. If all goes to plan, you’ll get most of the spent oil into your container.