How to replace transmission fluids?

Ordered some Amsoil trans fluid from Jordan and to be honest I never replaced the trans fluid before on my sti nor any car i have owned. Did plenty of oil change but never trans. Would anyone be willing to give me a step by step on how its done. Thanks

Have an 2005 sti

Rek and I just did it in my 04 and once you lift the car there is a drain plug around the middle of the tranny use a braked bar undo the plug and just let the fluid drain once done. Out the plug back it tighten it lower the car and go in the engine bay fund the transmission dipstick which is on the passenger side of the tranny by the firewall put your funnel in and fill up should be 4 quarts if I'm not mistaken. Also use Subaru fluids when it comes to doing the maintenance on your STI. And when you purchase the trans fluid from Subaru get their stuff with extra S in it. All of this advise I have gotten from Rek888v2 dude is the most anal person I have ever met when it comes to maintenance. Hope this helps out

So IIRC, there are TWO drain plugs in the front. On mine, one required a t-70 bit that I got at Autozone or Advance. Then right behind that, there's another plug that needs to be undone.



The first bolt (NOT a t-70 in the pic) is just to the right and slightly above the center of the crossmember. The second drain bolt is along the centerline but further to the right. It's facing forwards and on the mini-oil-pan thingie. I think a lot of people strip that bolt and have to replace the whole pan.

After, everything drains, you'll wanna clean off the magnetic plugs, and put everything back together. The refill location is on the top of the trans, on the passenger side. You can do it without taking anything off, but removing the IC will make things easier.


For the rear diff, on your 2005 you'll probably need a slightly different fluid. You have a clutch-type diff that needs some extra friction modifiers. Anyways, there's two plugs on the back of your diff.



Undo the bottom one to drain, and the top one (temp sensor) to fill. I HIGHLY recommend getting some sort of hand pump. It makes filling the diff a breeze. Otherwise you'll need a turkey baster, or a few other methods (filling through holes in the trunk, etc...) that aren't recommended.

Defined Performance said:

Bang876, I sell AMSOIL Transmission packages to quite a few Subaru's. Never once have they switched back to OEM once they run AMSOIL in the trans. Just wanted to assure you on your purchase.

Click to expand...

Best stuff around.

Thanks everyone for your help especially Grinder for his well thought out step by step post.

rek888v2 said:

Ive never ran anything other than Extra S in any of my 6 speeds. I was told by many well to do Subaru techs and tuners to never use anything other than Extra S in the trans and the Subaru LSD fluid in the rear diff. I have no technical data on Amsoil so I cannot vouch for it but I have seen several 6 Speeds grenaded using other fluids as well as frying 2 rear diffs myself using another "well known" fluid.

Click to expand...

the difference between them is minute. the only negligible difference is sheer strength and better protection provided by the amsoil brand. Any transmission, rear diff, motor, it doesnt matter, they will blow up when you are hard on them regardless of what you put in them. all of the new competitive oil brands do pretty much the same with a small difference in between them all so just take your pick and change it when you are supposed to and dont ramrod on the shit and you will be fine...

rek888v2 said:

. Ive always been told and read that the Extra S was best for the 6 speed trans and the Subaru LSD with Friction modifier was best for the rear diff. I

Click to expand...

Does this still hold true for the 07+ that have a torsen rear diff? I was under the impression that the 07+ rear diffs used the same Extra-S as the transmission.

Rek thanks again for frying my brain with information