Introduction to the South Bend Clutch Upgrade

Upgrading the clutch on your Subaru WRX is one of the most rewarding modifications you can make, especially if you are pushing higher horsepower or simply want a more responsive daily driver. The factory clutch, while adequate for stock power levels, often struggles with the increased torque from even mild engine tuning. The South Bend Clutch stands out as an aftermarket solution engineered to handle the unique demands of the Subaru drivetrain—providing reliable power transfer, improved pedal feel, and long-term durability. Many enthusiasts consider South Bend Clutch products the gold standard for WRX performance builds, and for good reason.

This guide covers the entire installation process from start to finish. Whether you are an experienced DIY mechanic or a first-time installer, the step-by-step instructions, torque specifications, and pro tips included here will help you complete the job safely and correctly. By the end of this article, you will have a clear understanding of what it takes to install a South Bend clutch on your Subaru WRX and the performance benefits you can expect.

Tools and Materials Required

Before you begin, gather all necessary tools and parts to avoid unnecessary delays. Having everything on hand ensures a smooth workflow and reduces the risk of mistakes.

  • South Bend Clutch Kit (includes pressure plate, disc, bearing, and alignment tool)
  • Basic hand tools: socket set (metric), wrenches, screwdrivers, pliers
  • Torque wrench (capable of ft-lb and in-lb ranges)
  • Jack and jack stands (preferably 2-ton or higher capacity)
  • Transmission jack or floor jack with a wooden block
  • Transmission fluid (check your WRX year and model for spec)
  • Brake cleaner and shop towels
  • Safety glasses and mechanic gloves
  • Penetrating oil (for rusted bolts)
  • Pilot bearing puller or slide hammer (if needed)
  • New flywheel bolts (recommended) and flywheel resurfacing service (if reusing OEM)

Preparation and Safety

Proper preparation is critical for a hassle-free clutch replacement. Follow these steps to set up your workspace and vehicle.

  • Park the vehicle on a level, solid surface. Engage the parking brake.
  • Disconnect the negative battery terminal to prevent electrical shorts or accidental engine starts.
  • Allow the engine and transmission to cool completely if the vehicle has been driven.
  • Raise the vehicle with a floor jack and securely place jack stands under the frame rails. Never work under a car supported only by a jack.
  • Remove the wheels (if necessary for better access) and set them aside.
  • Place a drain pan under the transmission to catch any fluid that may leak when removing the driveshaft or transmission.

Removing the Factory Clutch and Transmission

Step 1: Drain the Transmission (If Needed)

If you plan to replace the transmission fluid, now is the time to drain it. Locate the fill and drain plugs on the transmission housing. Use the appropriate size hex bit or socket to remove the fill plug first (ensures you can refill later), then the drain plug. Let the fluid drain into a suitable container.

Step 2: Remove the Driveshaft

Subaru WRXs use a driveshaft that connects the transmission to the rear differential. Using a marker or painter's tape, mark the orientation of the driveshaft flanges to maintain balance upon reinstallation. Remove the four bolts at the differential flange, then slide the driveshaft back slightly to disengage it from the transmission output shaft. Support the driveshaft so it does not hang freely, then remove it from the vehicle.

Step 3: Disconnect the Shift Linkage and Electrical Connectors

Remove the shifter linkage by unclipping or unbolting the link from the transmission. Unplug the reverse light switch and any other electrical connectors (speed sensor, neutral safety switch). Also, remove the starter motor bolts and set the starter aside—leave the wire connected or carefully disconnect it.

Step 4: Remove the Transmission Mount and Crossmember

Place a transmission jack or a floor jack with a block of wood under the transmission pan. Slightly raise the transmission just enough to take its weight off the mount. Remove the bolts that secure the transmission mount to the crossmember, then remove the crossmember bolts. Lower the transmission slightly to access the bellhousing bolts.

Step 5: Unbolt the Bellhousing and Separate the Transmission

Remove all bellhousing bolts. Subaru transmissions can be stubborn; use a pry bar gently to separate the engine and transmission. Be careful not to damage the mating surfaces. Double-check that no wires or hoses are still connected. Once separated, carefully lower the transmission out from under the car. This step is easier with a helper.

Step 6: Remove the Old Clutch Assembly

With the transmission out, you now have access to the flywheel and clutch. Remove the six pressure plate bolts in a crisscross pattern to avoid warping. Lift off the pressure plate and clutch disc. Inspect the flywheel surface for scoring, heat cracks, or warping. If the flywheel is glazed or has grooves, it should be resurfaced or replaced.

Inspecting and Preparing the Flywheel

A common mistake is installing a new clutch on a worn or damaged flywheel. The flywheel must be smooth and flat for the new clutch to engage properly. Use a brake cleaner to remove any oil or residue. If you see blue discoloration, deep grooves, or hot spots, have the flywheel professionally resurfaced or replace it with a new unit. Some South Bend clutch kits recommend using a lightweight flywheel for improved throttle response, but you can also reuse a resurfaced OEM part. Always use new flywheel bolts, torqued to specifications (usually around 75–90 ft-lb for Subaru WRX, but always verify your model’s service manual).

Installing the South Bend Clutch

Step 1: Position the Clutch Disc

Using the included clutch alignment tool, insert it through the center of the clutch disc and into the pilot bearing in the crankshaft. Ensure the alignment tool fits snugly—it will hold the disc in place while you install the pressure plate. The disc should be oriented with the "FRONT" or "FLYWHEEL SIDE" label visible, typically the longer hub facing the transmission.

Step 2: Install the Pressure Plate

Place the pressure plate over the clutch disc, aligning the dowel pins on the flywheel. Hand-thread the six pressure plate bolts evenly. Once all bolts are started, tighten them in a star pattern to the specific torque value provided in the South Bend clutch kit instructions (usually around 35–40 ft-lb). Do not overtighten, as this can distort the pressure plate.

Step 3: Remove the Alignment Tool

After torquing the pressure plate, remove the alignment tool. Spin the clutch disc by hand to ensure it moves freely. If it binds, the alignment is off, and you should repeat the alignment and torque sequence.

Step 4: Install the Throwout Bearing and Pilot Bearing

South Bend clutch kits typically include a new throwout bearing. Apply a thin layer of high-temperature grease to the bearing contact surface and slide it onto the transmission input shaft. If you are using a pilot bearing (some models have a bushing), ensure it is seated properly with the sealed side facing the transmission.

Reinstalling the Transmission

This step requires patience and care. A misaligned transmission can damage the pilot bearing, clutch disc, or input shaft splines.

  • Raise the transmission back up to the engine using the jack. Align the input shaft with the clutch disc splines and pilot bearing. It may help to wiggle the transmission slightly while pushing forward. Do not force it—if it doesn't slide in, realign the clutch disc using the alignment tool again.
  • Once the transmission is flush against the engine, install and hand-tighten the bellhousing bolts. Then torque them to spec in a cross pattern (typically 40–50 ft-lb).
  • Reattach the transmission mount and crossmember. Torque mount bolts to spec, then lower the transmission fully onto the mount.
  • Reinstall the starter motor, shift linkage, electrical connectors, and driveshaft. Make sure the driveshaft flange bolts are torqued to specification (often 35–40 ft-lb).
  • Refill the transmission with the correct grade and quantity of fluid. Subaru WRX transmissions typically require 3.5–4 quarts of 75W-90 GL-5 gear oil.
  • Reconnect the negative battery terminal.

Final Steps and Clutch Break-in Procedure

Before taking your WRX on the road, perform a thorough inspection. Check all bolts are tight, no tools are left in the engine bay, and the shift action is smooth. Start the engine and listen for unusual noises. Depress the clutch pedal several times to ensure proper pedal feel. If everything sounds normal, proceed to the test drive.

Clutch Break-in is Critical

South Bend Clutches require a proper break-in period to ensure optimal performance and longevity. This typically involves 300–500 miles of normal driving. During break-in, avoid aggressive launches, hard acceleration from low RPM, and allow the clutch to fully engage before applying heavy throttle. Vary your driving speeds and avoid highway cruising at a constant RPM for long periods. After break-in, the clutch will have fully mated to the flywheel and pressure plate, delivering its intended power-holding capacity and feel.

Performance Gains of a South Bend Clutch

Switching to a South Bend clutch provides tangible improvements that go beyond simply holding more power. Here are the key performance advantages:

  • Increased Torque Capacity: South Bend clutches are designed with high-friction materials and reinforced pressure plates that can handle 400–600+ ft-lb of torque, depending on the stage. This eliminates clutch slip under WOT in higher gears, which is common with stock clutches on modified engines.
  • Improved Engagement Feel: Unlike some heavy-duty clutches that feel binary (on-off), South Bend clutches are engineered for progressive engagement. This makes daily driving much more tolerable while still offering rapid shifts for track use.
  • Reduced Flywheel Noise: Many aftermarket clutches introduce chatter or gear rattle. South Bend clutches incorporate damper springs and precisely balanced components to minimize noise without sacrificing clamping force.
  • Longer Service Life: With stronger materials and better heat dissipation, a South Bend clutch typically lasts longer than OEM units, especially when driven hard. Their ceramic or Kevlar-based disc materials resist glazing from hard launches.
  • Better Throttle Response: The combination of a lighter flywheel (if upgraded) and reduced rotating mass from the pressure plate allows the engine to rev more freely, improving both acceleration and drivability.

Many WRX owners report a noticeable difference in how the car performs after the clutch upgrade, particularly when paired with a tune or other boltons. For a deeper dive into clutch technology, check out this South Bend Clutch official website for product specifications and stage recommendations.

Common Installation Mistakes to Avoid

Even experienced mechanics can make errors during a clutch swap. Watch out for these pitfalls:

  • Incorrect Torque: Under- or over-tightening pressure plate bolts can lead to clutch chatter or pressure plate distortion. Always use a torque wrench and follow the South Bend manual precisely.
  • Contaminated Friction Surfaces: Oil, grease, or dirt on the clutch disc or flywheel will cause premature slip and shudder. Clean all parts with brake cleaner before assembly.
  • Ignoring Flywheel Condition: Installing a new clutch on a warped or glazed flywheel guarantees poor performance. Resurface or replace as needed.
  • Improper Clutch Alignment: Even a slight misalignment can make transmission installation impossible or damage the pilot bearing. Use the alignment tool and double-check before torquing.
  • Forgetting to Bleed the Clutch Hydraulic System: If you disconnected the clutch slave cylinder or replaced hydraulic components, you must bleed the system to remove air. A soft pedal or disengagement issues often stem from air in the line.
  • Neglecting Transmission Fluid: While not directly related to the clutch, low or old fluid can cause shifting issues that mimic clutch problems. Always top up with fresh fluid of the correct spec for your Subaru WRX model year.

For additional guidance, many Subaru enthusiasts rely on forums like NASIOC to share installation tips and troubleshooting advice specific to their year and model.

Conclusion

Installing a South Bend clutch on your Subaru WRX is a rewarding project that dramatically improves the driving experience and reliability of your vehicle, especially if you are targeting higher power levels. While the process requires time, patience, and mechanical skill, the step-by-step instructions provided here will help you complete the job successfully. Remember to follow the break-in procedure, double-check all torques, and use quality tools. The result will be a clutch that feels great on the street, performs on the track, and stands up to abuse mile after mile. For those considering a performance build, the South Bend clutch is a solid investment—one that integrates seamlessly with the Subaru platform. Happy wrenching, and enjoy your upgraded WRX!