Gear Set Solutions - 2002 Subaru Impreza WRX

The front-differential case... 

   

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The front-differential case was removed last, and only because the ring-and-pinion gears needed replacing as well. Shown here is the ring gear being removed from the front diff.

4) Constantly Stuck Between The Top Of First And The Power In SecondThe thing on every WRX owner's mind is the six-speed STi transmission. Yes, this is definitely the best option for some in-between ratios; however, the expense of the transplant is not cost-effective for some of the grassroots racers, nor will it be legal under some series' rules, which require a standard transmission setup.

Changing the gear ratio in the factory box is a very effective way to go about it. There are gear sets available that help to make first gear usable by making it just a little taller, and second gear a little shorter.

5) Transmission Makes Noise During DecelerationThis is a common problem, but technically not a problem at all. It's just a matter of inconsistent factory backlash in the ring-and-pinion gear. Some models do it more than others.

The Subaru dealership can fix the problem, but not with performance in mind. The dealership will replace the 27 -pound flywheel with a heavier model to keep the gearbox loaded, thus eliminating a decelerating noise.

The driveshaft is then removed... 

   

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The driveshaft is then removed from the drive pinion shaft (pinion gear), which is replaced as a set with the new ring gear. The driven shaft carries first through fifth driven gears.

Going the opposite direction with the flywheel weight will not get rid of the noise, nor will it increase it. The lighter flywheel will be noticeable in how quickly the car finds its powerband. Suggestion: Get over the noise. It's not a big deal, and certainly not worth compromising power.

In our research we have come up with a gear set that can take care of most of the rally and road racers complaints. Gimmie Gears & Accessories offers a "Sport" ratio that is most effective across the board.

The taller first gear of the sport ratio tends to fill the first to second void, and when you shift through the rest of the gears, you have a slightly shorter than stock rpm drop (approximately 750 rpm per gear), keeping the WRX in its desired powerband. The gear set has fewer, yet bigger and stronger teeth, offering the necessary strength for even heavily modified WRXs.

We contacted GT Motorsports, in Rancho Cucamonga, Calif., about handling the gear install for us. Follow along as we see exactly what it takes to do a performance upgrade inside the 2002 WRX five-speed gearbox.

From GT MotorsportsBased on a well-known video game (Gran Turismo), we visualized a new service concept. This concept provides the customer with the ability to install a wide range of performance parts all at once. These performance parts can be selected and installed in one full sweep, or in stages.

The performance parts are available within today's automotive aftermarket and with the dream of bringing the game to life, Certified Automotive Group, INC(CAG,I) started the wheels rolling.

All of the driven gears are... 

   

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All of the driven gears are then removed from the shaft with a gear puller and placed in order for ease of reassembling. A substantial amount of parts will be reused with the new gear set, so keeping them in order is very important.

With the game's theories in mind, CAG,I created GT Motorsports, one of four automotive shops that fall under the CAG,I. The four automotive facilities consist of: Certified Auto Care, a full service repair shop, an 11 bay facility with ASE certified technicians. Certified Care Transmission is a full service transmission facility with four bays and three lifts. Under-car Specialists is a full service suspension, alignment, muffler, and tire facility with six lifts. GT Motorsports is a full-service performance shop with an in-house machine shop.

With each shop providing an automotive service specialty, the full gambit of automotive needs are covered. And GT Motorsports' access to the latest in computerized automotive equipment ensures no service or feature is left out.

For example, our wheel balancing equipment will not only balance all four wheels, but can also calculate the correct placement of each wheel for the optimum balance of your vehicle. With the all- wheel dyno, we can provide crucial horsepower data needed in today's competitive environment.

The repair facilities allow you to prep for your upgrades. This is a combination of service and technology.

All of the drive gears are...        read full caption All of the drive gears are pulled off of the stock transmission main shaft, along with the rest of the assembly that's to be reinstalled onto the new main shaft. Taking your time when tearing down the assembly is extremely important. Without proper care, it would be necessary to replace a good amount of easily damaged parts. We had no such problem with the experts at GT Motorsports; however, we did replace all the internal bearings as a precaution and recommend you do the same, especially if you're upgrading due to failure.

Once all of the parts are...        read full caption Once all of the parts are removed and cleaned, a thorough inspection of everything is necessary for a smooth reassembling. Order any parts that show signs of ill wear, as they can easily accelerate wear on the new gears. Once everything is accounted for and in perfect condition, continue on to the rebuilding process.

All of the new ratio drive...        read full caption All of the new ratio drive and driven gears are then carefully pressed onto their respective shafts with a shop press, so as not to damage any bearings or accessories. When both of the shafts are complete, simply reverse the disassembly process. Some special gaskets, sealant and tools are required, so it's highly recommended that you go to an experienced shop. There are special ways to remove each and every part in the assembly. A single mistake can be costly.