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DIY: Transmission Fluid Change

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310K views 58 replies 32 participants last post by  jeff0000  
#1 ·
For everyone that doesn't like way the 5spd shifts, and wants to make it feel much better, a transmission fluid change is definately a good start. While i will not comment on what brand of fluid to choose from, i will outline the steps involved in changing the trans fluid. Let's take a look...

Tool Required:

12mm socket
3/8in drive ratchet
Flathead Screwdriver
T-70 TORX bit
Jacks and jack stands (depending on how low your car is)
3.8 quarts of your favorite juice!

Step1: Ok, this is not a MANDATORY step, but for the 10 min it takes to remove the intercooler, the rest of the job becomes much easier. So, the first step is, you guessed it, remove the intercooler! As you can see in the pictures below, there are two (2) 12mm blots that hold the BPV onto the intercooler. Remove those, and put them somewhere safe. The BPV should come off, but don't remove it from the car, just let it sit there, disconnected.

View attachment 73100

Step 2: On either side of the intercooler, there are two (2) more 12mm blots that hold the intercooler down. Remove those, and put them in a safe place too.

View attachment 73101

Step 3: Once the intercooler bolts are removed, you will see that the intercooler is still connected... to the turbo, and to the throttle body. The rubber hoses that connect the intercooler to the respective parts are held tight by metal fasteners. With a flathead screwdriver, loosen each one of the fasteners so that they can move freely around the rubber, but do not remove them completely. Now, there really isn't directions for this part, but you'll need to dance and coax and curse and pray, but if you wiggle the intercooler enough, the rubber tubes will slide off of the turbo and throttle body, and it will be *almost" compeltely off now. There are still vacuum tubes that are connected to the intercooler core... don't worry about those, just take the intercooler, and flip it over onto the engine to get it of your way, as seen in the picture. Hey! Now were ready to change the tranny fluid!

View attachment 73102

Step 4: At this point, you need to decide whether or not your car is high enough off the ground (or your small enough to fit under your car) without using jacks. If you can, great! If not, then you'll need to jack the car about half a foot off the ground, as it makes getting to the transmission drain plug much easier.

Step 5: Once you're comfortable with being under the car, you'll want to do one thing before you drain the oil... go back to the engine compartment, and look for a long, gold dipstick with a loop at the top, located pretty close to the pitch mount, coming out of the transmission. This is the tranny fluid dipstick, and is also where you will refill the trans. Before you drain the fluid, remove this dipstick, and put it somewhere CLEAN!!! We do this because removing this plug relieves pressure in the trans, and allows the trans to empty quicker and get more junk out. Now go back under the car.

Step 6: Once you slide under the car, you'll look up at your transmission, and you'll see one of two things. Depending on the year of your car, the transmission fluid drain plug will be a 17mm lug (02-05 i think), or a TORX T-70 star shaped lug (06+ i believe). Either way, it will be one of those. 17mm sockets are easy to find anywhere, but a TORX T-70 is literally impossible. You can order one online, but they DO NOT sell these in stores. However, i bought a T-60 at Pepboys, and while i WOULD NOT advise doing this, i used a T-60, and it worked just fine.

Step 7: When the trans is done draining, put the drain plug back in, get out from under the car, and lower the car down. Go back to the engine bay, grab a long funnel, and stick the end in the tube where that tall gold dipstick came from. Put about 3 1/4 quarts in the trans case, and check the level. Continue filling and checking under the fluid is at the full mark. The trans can only hold 3.8 quarts, so DO NOT put all four quarts in!

Step 8: When you are finished filling the trans, make sure the dipstick is clean, and put it back into the trans. You'll need to put the intercooler back on, which is even worse than taking it off. I can't really give you advice here, just wiggle it until it fits on, and then do the reverse of the first sets of instructions. When everything is all tightened down, let your car warm up a few minutes, and go for a nice drive, and make sure to notice how you can actually get into reverse, and slide into first at speeds of over 1mph!!!
 
#7 ·
2004 wrx 5 spd manual transmission fluid replacement

This is a similar write up to nocturnal but in another persons words and experience. let me know if it helps u.

I just changed my 2004 wrx 5 spd tranny oil and it had a torq 70 plug. found a torq 60 for 8.99 @ ace hardware ( not recommended but heard on here or NASIOC works without stripping and its true), used a regular ratchet ( make sure not to use a shorty, not enough leverage needed to break these bolts).

So, crucial steps to changing transmission oil that I learned the hard way.

1. Use a open drain pan of 4" or a drain pan with a large hole. The spigot of oil is about an inch or two wide when coming out and it comes fast watch out. warm oil drains easier but make sure its not too hot or it will burn you if it splashes. i raced home to get some sunlight to work in and my oil sizzled on my arms a bit when my pan proved unworthy. It was not lined up with the drain hole perfectly since i thought it would dribble out. Oil went everywhere. I hustled for newspapers and decided mothers rose garden dirt was quickest solution.

2. Buy a large metal sheet drain pan from the auto store for cheap, it would have saved my driveway and allowed me to clean up the mess.Use as emergency pan in case "**** hits the fan pan" I did not take the dipstick out before draining and had no idea it flows like a water fall out of the tranny even with it in. So use a deep drain pan with either a tarp or some emergency ground covering unless you don't care about losing 3.8 qts of dirty stank oil under your car.

I got to the plug by jacking one side of the car with the cheapo trunk jack, set some bricks around the jack in case the jack breaks, long side up, hopped under the car from under front bumper, undid the plug with decent amount of force. THIS SETUP IS NOT RECOMMENDED AS RISK IS DEATH. Buy a real jack like 2.5 ton and some jackstands for emergencies. I am broke and my tranny had no oil so I was in dire circumstances lol ( stupid in hindsight)

let car drain and lower car to get out all of fluid.raise, replace fluid without removing damn I/C. Hint: buy a long neck funnel and wiggle it a bit to make the oil go down faster(takes a while). Measure your dipstick once you get close to 3.5 qts or so. You are now done.

RESULTS:

Took for a test drive and sweet Jesus its night and day when going into reverse or 1st from a park or N and a lot better when on the roll.

Replaced with Redline 75w90ns. bought direct

When I took out the tranny plug it had a large piece of metal on it either a part of a magnet or a tooth of a gear:confused:, it seemed like metal, will further inspect and maybe post a pic. The plug was crazy dirty and looked like it had never been cleaned.:screwy:

Good luck all

and props to Big Mountain Sky, Peaty and Unabomber for their FAQ and How To-s. Also thanks to nocturnal for his write up which i used quite a bit for this.

Ryan
attached a pic of my car.
San Diego,CA
 
#8 ·
Bump -- Hey, its my first time getting really under my car and I can't seem to find the tranny drain plugs....I have an 04 WRX....i used the T-70, but where that thing fit i couldn't even move the wrench 'cus there was no room.....can anyone post up pictures of exactly where the plugs are? THANKS!
 
#9 ·
Find the end of the plastic splash guard that covers the bottom of the engine. the oil plug and pan ill be there. Then look a few inchs further back and you will find the transmission. The plug for the trany oil is right next to a crossmember or part of the frame that the tranny sits on. you can see it better from the side. theres only 2 plugs under their. you will find it.
 
#10 ·
Pretty straightforward...

Hi everyone, thanks for the help here.

I did this yesterday on my 05 wrx wagon...

My car does have the huge torx bolt to drain--I'm guessing so that people don't mistake it for the oil drain plug. Nice part is that you don't have to remove the plastic shield to get to it.

I did not remove the intercooler, but just used a funnel with a long (maybe 1.5 ft) flexible hose attached, to refill the fluid through the hole the dipstick came out of.

The dipstick read "full" at about 3.7 qts or so on my car.

I was worried about the torque on the drain bolt, and asked a former mechanic friend who told me just to snug it, and tighten 1/4 or 1/2 turn past that, but that there's no need to get overly anal unless you're doing internal engine work or tire lug nuts. Anyone out there confirm/disagree w/ this advice?

thanks!
 
#11 ·
Sorry to bring this one back, but I did this tranny fluid change in my '04 WRX today. Everything was fine, the drain plug was not the T70, it was the regular socket, so I was lucky in that sense.

I was sure the pan was drained as much as it could be with the car raised up, it was barely dripping any more. I torqued the bolt back in the pan and lowered the car down.

I was ready to fill it back up with 3.7 qts. of fresh oil (I chose Valvoline non-syn 75w90 from Auto Zone).
Using a flexi-funnel, I filled the dip-stick tube with 3 full qts. from 3 bottles of fluid.

Before adding any more, I waited a few minutes and then checked the level and it showed as being very slightly above full. So I figured the car may be a little warm or the new oil may still need to settle. Throughout the next 15-20 minutes I kept checking the dip-stick level a few times, and it wasn't really going lower than slightly above the full line.

What could this mean? I'm pretty sure it was fully drained, and I know I only put 3 qts. in so far.
Also, I figured whatever small amount of old oil that is usually left and unable to drain out wouldn't cause the level to be full with only 3 fresh qts. poured in.

Did I not wait long enough for the oil to settle? I thought with the car being mostly cool, it wouldn't take any longer to settle than motor oil.

I wanted to drive it around the block to feel the gears, so I did that without waiting any longer since it was showing as full. Everything felt fine, but now I have to wait longer for fully cool to check the level again.

Should I assume it's actually full with only 3 new qts? If so, how???
 
#12 ·
Should I assume it's actually full with only 3 new qts? If so, how???
What was the volume of fluid you drained?

I've yet to meet anyone that's had to use 3.7L.

What volume did you measure coming out?

I overfilled mine once too.
 
#16 ·
Yeah I was on a level surface before I filled the tranny. And I only drove it after I got impatient waiting for the new oil to hopefully settle. Before that, when I was checking the level constantly, the engine was mostly cool already.

I'm kind of worried about why it was showing as full with only 3 new qts.
I'll check it again once cool tonight.

???
 
#17 ·
Wait for tomorrow. That oil is quite thick. You could also email the transmission shop I just posted up. They know Subaru transmissions better than most anyone.

I always change the rear differential fluid when I do the transmission. I start draining the transmission first, then move onto the differential to completion allowing the transmission to drain for that entire time.
 
#19 ·
For you guys that said you overfilled before, did you mean you had also drained completely, and it overfilled after putting less than 3.7 qts. in like me??

Also, I only did the tranny, not the rear diff.
Overfill? Yes, drained completely as described. The first time I put nearly the entire 3.7 in which way overfilled it. This time I carefully measured 3.5 and it was still slightly overfull. Next time I'll put 3.0 and add from there.

I'm at a loss as to why 3.0 filled your gearbox. I have a 2004 as well. Did you take a drive prior to changing the fluid to get it hot so it would flow and drain more easily? I always do.

Change the rear differential fluid if you never have. I've always used Redline 75-90W Synthetic in the rear differential, but any quality 75-90W will do well. Getting the fill level correct is a no brainer - it take less than a quart.
 
#20 ·
Yeah I had driven earlier to pick up the oil, and it cooled for at least a few hours before I started. Then I only started it again to drive the car up pieces of wood to jack it up. So if it was warm all, only a little. And the oil drained out crazy fast and strong, probably due to the warmth and dip-stick being removed.
 
#21 ·
I start draining while still hot as I do with engine oil as well. As hot as I can stand it without getting burned. I just pull the dipstick out an inch or so while draining.

Let us know how you make out. :)
 
#22 ·
So I checked again just now after a few more hours, everything definitely feels cool to the touch.

Same level on the dip-stick. Basically the level is perfect- right at the fill dot after I poured in 3 quarts exactly.

What is going on???

There seems to be no way there could have been enough old oil left in the case to equal about .7 quarts total. WTF??????

Worried still.
 
#23 · (Edited)
What is going on???
Nothing.

I haven't yet measured how much came out, but it is still sitting in a pan. Not sure if I have any thing to measure it with and God I hate the smell lol.
I on the other hand am sure you do have something to measure with. What containers did the gear oil you added to the gearbox come in?

I mean it's strange that its exactly at full after 3 right now.
You likely only removed ~3 or so. Everyone tends to overfill because they don't remove all the gear oil.

If the level on the dipstick is correct, then the level on the dipstick is correct. You can't fix it. Keep on checking it if you are concerned but in general I'd not be concerned. This is what typically happens. I've done this. Many people have done this.

Just check the fluid again a couple times but again, if it's OK, well it's OK.
 
#24 ·
Thanks. This is what I am leaning towards, as nothing else really makes sense if the boxes are in fact able to hold 3.7qts.

I will keep checking it until I feel safe lol, but if I feel like gettin' dirty again, I will throw the drained oil back into the bottles to see how much it shows. Although those bottles are annoying because the full level of them is always above the highest number/notch on the side, ugh.. but at least I still have the 4th unopened bottle to go by...
 
#25 ·
I've been in your shoes. I added over 3 to mine first time I drained, resulting in overfilling. I think the gear oil is so viscous that not all of it comes out. I mentioned measuring what you removed to try to ease your nerves but ultimately it doesn't matter how much you removed; all that matters is what's in there now. If it's OK, that's that. Enjoy the car, and keep checking until you're sure.
 
#26 ·
2009 wrx?

I'm planning on doing this, this weekend on my 09 WRX. Does anyone know if the instructions are the same, especially regarding what size torx driver I might need?
 
#27 ·
Thanks for all the replies! :p

Anyhow, just changed the tranny oil on my 09 WRX. And yes it does use the T70 bolt for the drain plug. I would highly recommend a breaker bar to break it loose. I got the T70 driver at autozone like someone else mentioned. I also picked up a funnell with a plastic accordian type hose for $3 which saved me removing the intercooler. :) I put in 3 quarts of the mythical "Extra-S" oil and that put me at the lower mark on the dipstick. I put in another ~1/4 bottle and now I'm in between Low and Full. Going to drive it around today and check the oil again before adding more. Thanks everyone for the helpfull info! Doing this was a snap and saved me $150 that the stealership wanted...:cool:
 
#33 ·
no problem, i am also going to add to this a warning to be careful and not make a mistake i did. While refilling the trans it is very easy to overfil the fill tube which unless your funnel is the perfect size can cause some trans fluid to leak out. This isnt a huge deal until you look under the car to check for leaks and see the small puddle. It can easily seem that the leak is coming from the drain plug. Overall though a very good writeup and pretty simple change.