Understanding the 2015 VA Chassis Drivetrain
The 2015 model year marked a revolutionary shift for the Subaru WRX. Transitioning to the VA chassis, Subaru introduced the FA20DIT turbocharged boxer engine paired with the robust TY85 6-speed manual transmission. As we move through 2026, these vehicles have become highly sought-after enthusiast platforms, meaning many are now due for their second or third clutch service. For a beginner, a 2015 Subaru WRX clutch replacement can seem intimidating due to the Symmetrical All-Wheel-Drive layout, front differential integration, and dual driveshafts. However, by breaking the procedure down into manageable phases, this job is entirely achievable in a home garage.
Unlike the older 5-speed models, the TY85 6-speed transmission features a 25-spline input shaft and requires precise attention to fluid separation and shift linkage alignment. This guide will walk you through the exact procedure steps, ensuring you avoid the common pitfalls that trap novice mechanics.
Essential Tools and OEM Part Numbers
Before lifting the vehicle, gather your parts and specialty tools. Using the correct alignment tool and fluid is non-negotiable for the longevity of your TY85 transmission.
| Component / Tool | Specification / Part Number | Notes |
|---|---|---|
| OEM Clutch Kit | Subaru 30210VA110 (Disc) / 30210VA040 (PP) | Exedy SBC1828 is the exact OEM equivalent. |
| Flywheel | OEM Single-Mass (or ACT Sprung Hub) | Resurface if within thickness spec, otherwise replace. |
| Transmission Fluid | 75W-90 GL-5 Gear Oil (3.5 Liters) | Main case capacity. Do NOT use GL-4. |
| Front Diff Fluid | 75W-90 GL-5 Gear Oil (0.5 Liters) | Separate fill plug on the TY85 6MT housing. |
| Specialty Sockets | 36mm (Axle), 14mm/17mm (Bellhousing) | Deep impact socket recommended for axle nuts. |
| Clutch Alignment Tool | 25-Spline Subaru Alignment Tool | Mandatory for guiding the TY85 input shaft. |
Phase 1: Drivetrain Fluids and Front Axle Removal
Draining the Fluids
A common beginner mistake is assuming the 6-speed transmission and front differential share a single fluid reservoir like the older 5-speeds. The TY85 6MT has isolated chambers. Place a large drain pan beneath the vehicle and remove both the main transmission drain plug and the front differential drain plug using a T70 Torx or 1/2-inch square drive, depending on your specific casting. Allow the 75W-90 GL-5 fluid to drain completely.
Freeing the Front Axles
To drop the transmission, the front CV axles must be disconnected from the differential stubs.
- Remove the front wheels and peel back the grease boot covers if necessary to access the 36mm axle nuts.
- Break the 36mm axle nuts loose while the car is still on the ground and the brakes are applied. Pro-Tip: Use a breaker bar and avoid using an impact gun on the staked nuts to prevent hub bearing damage.
- Lift the vehicle securely on jack stands placed on the factory front pinch welds.
- Unbolt the lower control arm ball joint or strut-to-knuckle bolts to allow the steering knuckle to swing outward.
- Carefully slide the axle out of the hub, then use a pry bar to gently pop the inner CV joint off the transmission stub axle. Support the axles with bungee cords to prevent stress on the outer CV boots.
Phase 2: Unbolting the 6-Speed TY85 Transmission
Disconnecting the Driveshaft and Linkages
Move to the rear of the transmission. The 2015+ WRX 6MT connects to the rear driveshaft via a bolted flange coupling, an upgrade from the older roll-pin designs. Unbolt the four flange bolts and support the driveshaft. Next, disconnect the hydraulic clutch line from the release fork (be prepared for a small amount of DOT 4 brake fluid to leak). Unplug the reverse light switch and neutral position sensor harnesses.
Supporting the Engine and Dropping the Crossmember
The transmission crossmember also serves as a primary engine mount support. You must support the engine from above using an engine support bar resting on the strut towers, or place a jack with a block of wood under the engine oil pan (avoiding the drain plug). Remove the pitch stopper mount from the top of the engine, then unbolt the transmission crossmember. Slowly lower the transmission jack, guiding the TY85 input shaft out of the clutch disc and pilot bearing. The 6MT weighs approximately 115 lbs, so ensure your transmission jack is securely strapped.
Expert Insight: Inspect the clutch fork pivot ball while the transmission is out. The TY85 is known to wear a groove into the pivot ball over 60,000 miles. If a groove is present, replace the pivot ball (Subaru Part # 30537AA030) to prevent premature throwout bearing failure and clutch chatter.
Phase 3: Flywheel Resurfacing and Clutch Alignment
With the transmission on the bench, remove the six 14mm pressure plate bolts in a crisscross pattern to relieve spring tension evenly. Remove the old clutch disc and pressure plate. Inspect the flywheel surface for heat spots, bluing, or deep grooves. For the 2015 WRX, taking the flywheel to a local machine shop for a resurface is highly recommended, provided it meets the minimum thickness specification (typically stamped on the edge of the flywheel).
Aligning the Clutch Disc
Clean the flywheel with brake cleaner and a lint-free cloth. Place the new clutch disc against the flywheel, ensuring the side marked 'FW SIDE' or 'FLYWHEEL SIDE' is facing the engine block. Insert your 25-spline alignment tool through the disc and into the crankshaft pilot bearing. Install the new pressure plate, hand-threading the six 14mm bolts. Tighten them in a star pattern to 27 lb-ft (37 Nm) to ensure the diaphragm spring is compressed evenly. Remove the alignment tool.
Phase 4: Reassembly and Critical Torque Specifications
Reinstallation is the reverse of removal, but precision is required when mating the transmission to the FA20DIT engine block. Apply a thin layer of high-temperature grease to the input shaft splines and the release bearing contact points, but avoid over-greasing, as excess grease will sling onto the clutch friction material and cause immediate slipping.
| Fastener Location | Torque Specification | Thread Size / Notes |
|---|---|---|
| Flywheel to Crankshaft | 69 lb-ft (94 Nm) | Use new OEM stretch bolts if applicable. |
| Pressure Plate to Flywheel | 27 lb-ft (37 Nm) | Tighten in a crisscross pattern. |
| Bellhousing to Engine Block | 37 lb-ft (50 Nm) | Ensure dowel pins are seated perfectly. |
| Transmission Crossmember | 63 lb-ft (85 Nm) | Verify engine pitch is level before tightening. |
| Rear Driveshaft Flange | 36 lb-ft (49 Nm) | Apply blue Loctite to flange bolts. |
| Front Axle Nut (36mm) | 162 lb-ft (220 Nm) | Stake the nut collar after torquing. |
Hydraulic Bleeding and Shift Linkage
Once the drivetrain is bolted back together, refill the main transmission case with 3.5 liters of 75W-90 GL-5 and the front differential with 0.5 liters. Bleed the hydraulic clutch system using the DOT 4 fluid reservoir and the bleeder valve on the transmission bellhousing. Pump the clutch pedal 15 times, hold, open the bleeder, close, and repeat until no air bubbles are visible.
Finally, reconnect the shift linkage. The 2015 WRX shift rod must be aligned according to the factory service manual marks. If the rod is rotated even one spline off, you will experience severe difficulty engaging reverse or 5th/6th gears. For further community troubleshooting on shift linkage adjustments, the NASIOC Transmission & Drivetrain Forum remains an invaluable resource for VA-chassis owners.
Beginner Pitfalls to Avoid
- Forcing the Input Shaft: If the transmission will not slide flush against the engine block, do not use the bellhousing bolts to winch it in. This will crack the aluminum bellhousing or bend the clutch disc. Lower it, realign the 25-spline tool, and try again.
- Ignoring the Rear Main Seal: With the flywheel removed, you have direct access to the engine's rear main seal. If it has over 80,000 miles, replacing it now (Part # 806700030) costs $15 and saves you a $1,000 labor bill later. You can source OEM seals and clutch kits via the Subaru Parts Online OEM Catalog.
- CV Axle Boot Damage: When prying the inner CV joints from the differential stubs, ensure your pry bar rests against the cast iron differential housing, not the aluminum transmission case or the rubber CV boot.
By following these structured procedure steps and respecting the specific torque specifications of the TY85 6-speed, your 2015 Subaru WRX clutch replacement will result in a crisp, reliable pedal feel ready for the streets or the rally stage. For premium replacement kits and fluid packages, retailers like FCP Euro offer excellent warranty coverage on drivetrain components.
