Steering and suspension parts are a lot like the brake system components. Their proper operation is vitally important to the safety of the driver and his passengers, but it is very difficult to determine how long it will be before any of these components will require attention. That’s why an inspection of all steering and suspension components is required at 15 month/15,000 mile intervals. Changes to these systems may be too gradual for the driver to even notice, leaving it to you to ferret out and correct any wear or damage that has taken place.
We won’t cover all of the steering and suspension checks here. There’s too much variation between different Subaru models to do an adequate job. What you’re looking for is anything that reduces the original precision of the steering and suspension systems. Perhaps the steering has a little too much play in it or the shocks and struts don’t handle the bumps in the road as well as they did when new. Specific tests for the Subaru model you’re working on can be found in the service manual.
Check the power steering system for dampness or other signs of fluid leakage. The power steering pump reservoir is a good place to start. If the reservoir is low, the fluid has probably leaked out, as it has no place else to go. Approved fluids for the power steering system include Dexron II, IIE or III.
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.
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
– 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.
Step 1: Once the car is up on jack stands / a lift, you want to support the transmission and remove the rear cross member. You will need to remove it later anyway, it also makes it much easier to work without it in the way. I used a bottle jack and block of wood to support the tranny, but im sure a transmission jack would work much better if you have one.
This picture shows the cross member removed.
Step 2: Once the cross member is unbolted you will need to unplug the 02 sensor, and unclip its harness from the cross member. It is held by two plastic clips that can be pushed out of the holes in the member without much trouble.
Step 3: Remove the bolt from the lower rod, I believe it is a 14mm. The nut on the other side is attached to the bracket, so you don’t need a wrench on it. I found that ratcheting wrenches work best for most of these bolts.
The bolt that needs to be removed is the one going through the rubber bushing shown in the upper right of this picture.
Step 4: Now you can disconnect the reverse lockout cable. It is held in with a pin that can be pulled out with a pair of pliers. I stuck an Allen wrench through the cam as shown in the Cobb short shifter install when I removed it just in case. There is a washer on the lockout cable that may be stuck in the grease, you will want to take it off and set it aside so it doesn’t get lost. The lockout cable can be seen on the left side of the picture above. You can now move the lower rod down, and move the lockout cable out of the way.
This procedure was performed on a MY04 STi with some modifications which may or may not be relevant for the purposes of this How-To. This procedure is only ONE way of removing the transmission and is not meant to be the be-all method. This is a DIY on your driveway process only. If you have access to a lift, this would be the preferred and safest method.
Perform this procedure AT YOUR OWN RISK.
This procedure allows you to remove the transmission from a Subaru STI for the purpose of gaining access to the clutch and flywheel system for inspection and or replacement.
This procedure allows you to remove the transmission without the benefit of a lift and is meant as a DIY for the weekend warrior. This is by no means a simple or easy procedure and it requires a good deal of strength. IT IS RECOMMENDED YOU HAVE A FRIEND THERE TO HELP. You will need a second pair of hands at times.
How does a lightweight flywheel improve performance? A transmission can be thought of as a fulcrum and lever in a car. First gear has a really long lever; second gear has a shorter lever, etc. The lever represents the mechanical advantage that gears give your vehicle. When your car is moving, you have two factors that are present during acceleration, one is driveline losses, which are constant and the variable, which is vehicle weight and the mechanical advantage supplied by each gear.
While changing to a lighter flywheel will give the user little to no changes on a dyno, the apparent changes are quite dramatic due to the greater mechanical advantage. Consider these made up figures for consideration: Drive line losses, 45 pounds and vehicle mass (weight) at the driveline (remember your gear’s mechanical advantage reduces your actual car weight). We know that within reason, vehicle mass is a constant.
Now imagine if you reduced the driveline loss from 45 to 35 with the use of a lightweight flywheel. Since the engine has less drivetrain losses to compensate for, this means the “gained” horsepower can be applied to moving the vehicle mass. Using mathematics, one can realize that the higher you go up in gears, the less effect that a lightened flywheel will have to the overall equation.
Are there any downsides to a lightweight flywheel? While the performance characteristics of a lightweight flywheel seem to be the perfect solution, there are compromises:
a. Low end performance is affected. This usually means that higher revs are necessary for smooth starts due to the reduced rotational mass. For drag racers, this can be a BIG issue.
b. Possible missfire check engine light.
c. Possible chatter, like missfire this affects some users and not others.
02-07 WRX: open
04 STi: “SureTrac” LSD
05-07 STi: “Helical” LSD
Rear Differentials: R160, R180
These were originally used in the Datsun 510, 610 and other IRS Datsuns. The “R” stands for Fuji Heavy Industries. The R180 was used in the front axle of Datsun 4×4 trucks (720, etc). The number represents the ring gear size in millimeters.
R160– 52lbs. WRX rear differential. It has a viscous LSD which is no better than an open differential since the unit is so tiny in this differential.
02-05 have a 3.54 gear ratio
06-07 have a 3.70 gear ratio
R160’s on 2.2L Legacy/Impreza’s have a 3.9 gear ratio
R180 – 64lbs. STi rear differential. It has a mechanical clutch type LSD.
04-05 R180’s have a 3.90 gear ratio
06-07 R180’s have a 3.54 gear ratio
02-07 WRX: Viscous coupling type
02-05 has a 1.1:1 gear ratio
06-07 has a 1:1 gear ratio
04-07 STi: DCCD (Driver Controlled Center Differential)
04-05 has a 1:1 gear ratio
06-07 has a 1.1:1 gear ratio
Do I need different front axles?
02-early 04 WRXs have female axles and need to use stubs that go inside the transmission . Late 04-07 WRXs use male ended axles that slide inside the front differential so there is no need for stubs. For the female axles, you need axle stubs, circlips, and seals to reuse the WRX axles (check out the seal differences link for part numbers). You can use the stubs from your 5MT. For the male ended axles, they just slide right into place with the correct seals and circlips. 04 STi front axles will work too.
5spd Subaru WRX five speed manual tips and tricks:
So you’ve got this noise coming from your 5spd transmission. It is starting to whine when you’re on/off the throttle. The sound seems to come right from below like around the shifter area. You may be a victim of the infamous falling apart center differential!
Don’t be too worried, transmissions are a dime a dozen! You still have the option to go 6spd or another 5spd transmission with different gear ratios if you choose.