Tranny Fluid Change

Tools needed:
21mm socket
3/8" drive torque wrench
cheater bar (not necessary)
ramps and jack stands
flexible funnel (must)

Other:
4qt. 75w-90 synthetic gear oil
1qt. Penzoil Synchromesh

My car is at about 60k miles. I do a lot of autox'ing and wanted to see how the tranny was holding up inside. On the drain plug, there is a magnet that collects debri from the internals of your tranny. You can't check the magnet without draining the fluid, so I decided to do a fluid change. Its a fairly simple procedure which requires only about an hour of your time or less.

1. Back the car up on ramps, so the back wheels are off the ground. I then jacked the front of the car up and used jack stands for support. The reason for jacking both sides of the car up was to get the tranny close to level for draining. It wasn't completely level, but leaning a little more to the front, but it shouldn't be a huge deal since thats where the drain plug is.

2. Make sure the car has had about 30 minutes to cool, if not the tranny fluid will come out at close to 180F. I attached a 21mm socket to my cheater bar, because I don't like struggling if a bolt is too tight. Once the bolt was broken loose, I stuck a large oil catch pan underneath the bolt. Make sure you back away from the bolt as far as possible when removing it. There is a lot of tranny oil, and when it comes out it is likely to splash. Also, make sure a fan is blowing on the area if you are in a garage, because it will start to stink. (see attached picture of bolt)

 

3. Clean the bolt magnet thoroughly. There is no reason to stick the dirty bolt back into the tranny. When I pulled my bolt, there was a lot of gray crud that looked like sludge. There was also some small metal fragments about a mm in size that were strongly attached to the magnet. To remove the metal fragments from the magnet, I used a telescoping magnet (like the one you fetch bolts with in your engine bay). I swiped the magnet across the bolt magnet and all of the fine metal fragments attached to the stronger magnet. I also used a wire brush to clean the threads of the tranny bolt. Take the metal washer off and clean all around that as well. (see attached picture of bolt crud)

4. Clean the tranny where the bolt was removed. This is just so that when the bolt is placed back into the hole, it will sit flush against the tranny. Tighten the bolt down and use a torque wrench to apply 32.5 ft.lbs. of torque.

5. Move to the top of the engine, right below your intercooler if you have a topmount still. There should be a dipstick sticking over your turbo heat sheilding. This is where you would check the tranny fluid, but it is also where you pour in the new tranny fluid. Pull the dipstick out and attach your flexible funnel. If you do not have a flexible funnel, you may have to remove the IC, so pay the $4 and get the good funnel. My 03 WRX requires 3.7qt. of the specified oil. I poured 3 qt. into the tranny and with any empty bottle, poured in .3qt. so that .7qt would be left over. I found this to be easier than trying to measure it on the funnel. Make sure you allow enough time for the oil to get into the tranny, because this stuff is like molasses. (see attached pictures of funnel and dipstick)

6. Replace the dipstick and get the car onto the ground. Check the fluid once the car is on the ground and level again. Go drive the car around for a few minutes so the tranny fluid heats up. Check the fluid again. Don't drive the tranny hard immediately. Allow the oil to get into the gears where it needs to be before you start getting on it. Check it the fluid every so often again just to make sure everything is good.

 

I noticed since the fluid change that the gear transition has been a lot smoother. When I put it into reverse to back out of my driveway it went right into gear, which surprised the hell out of me. Also, when I examined the fluid that came out of the tranny, it had a brownish hue, while the new stuff was kind of yellowish green. I used Mobil 1 synthetic gear lubricant. Make sure you don't mix oils, because just like engine oil, each manufacturer has a different blend of additives.

I would recommend this for anyone that has driven their car hard in the mountains, autox, drag, and track, or just hard in general.

 

Here are the pictures in chronological order. Sorry about not having good pictures of the tranny bolt, its hard to take a picture that close to something. Its also kind of difficult to see the crud on the bolt, but image a gray blob like axle grease. I will probably add up how to change your differential fluid this Saturday. So stay tuned...

I tried the cocktail now that I had to replace my tranny fluid again due to a clutch change. The cocktail definitely works better. It allowed me to shift from 2nd to 1st without grinding or having to be at a stop.

 

thanks for the DIY tom

 

2005 and later uses a Torx T70
And are you sure you want to use a synthetic gear oil ???

 

Good writeup, I've been meaning to try the gear oil cocktail sometime soon.

 

I read in both the owners manual and scoobymods that the gear oil should be synthetic, so thats what I added. Reverse has gone in the first time everytime I have shifted it since the fluid change.

 

Im goin to be changing mine soon
but im still open on the fluids currently i plan on running
valvoline 75w-90 (regular) 3qts and fill up the rest with Penzzoil Syncromesh.

Reason i think synthetics are too slick and the syncros are not working well with it
In fact if you search at scoobymods a few have mentioned probs with Mobil1 synthetics as tranny oil

 

Which gear ?
Rear differential ? or Tranny ?
I Use Amsoil Synthetics for the rear differential

 

Good job on the writeup. Be careful taking the car to SOG for the tranny fluid swap, as they stripped the crap out of my drain plug, and I had to buy a new one when I swapped it myself the next time...

--
Brian