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.
When removing the airbag from the steering wheel, be sure to turn the ignition switch to OFF, disconnect the ground cable from battery, and wait for more than 60 seconds prior to starting work. The airbag system is fitted with a backup power source. If the airbag system is serviced within 60 seconds after the ground cable is disconnected, it may inflate.
When storing a removed airbag module, do not place any objects on it or pile airbag modules on top of each other. If the airbag inflates for some reason when it is placed with its pad side facing downward or under any object, a serious accident may result. Do not drop the airbag modulator parts.
Please remember that if you have Cobb AccessPort, your real time map will be need to be reflashed after disconnecting the battery
2) Set the tires to straight-ahead position.
Do your best to park as straight as possible. We suggest straightening the wheel and driving forward approximately 15ft. Try having a friend help you with this.
3) Remove the airbag.
In order to remove the airbag, you will need a T30 TORX bit.
You will find the two bolts on the left and right-hand side of the steering wheel, approximately at 9 and 3 o’clock (refer to figure 1.0 in the “Reference Images” section of this installation guide).
These are lightly torque (~5 to 7.2 ft.lbs) and will not come out of the steering wheel.
Once these are loosened, you may gently remove the airbag.
You will immediately notice the airbag harness. There may be one or two plugs and one ground plug connected to the airbag. The ground is removed with another gentle pull. The main connectors, located on the center of the rear of the airbag, will have either one yellow or one yellow and one pick lock tabs. Use a small flat head to gently pry this upward. Place this yellow lock tab in a safe place (refer to figure 1.2 or 1.3 for applicable model year).
Your airbag is now ready to be removed! Please take great care in storing your airbag!