The most common signs of a bad clutch are slipping, where engine speed rises but the car does not speed up to match, a clutch that engages very high in the pedal travel, trouble getting into gear, chatter when pulling away and a burning smell. How long a clutch lasts depends mostly on how it is driven: many last somewhere between 50,000 and 100,000 miles, and some much longer, while frequent stop-and-go traffic, towing and hard launches wear one out sooner.
Signs of a bad clutch
- Slipping: the engine revs climb under load, most noticeably in a high gear going uphill or when accelerating hard, without the matching gain in speed.
- High engagement point: the clutch only bites near the top of the pedal travel, a sign the friction material is thin.
- Burning smell: a sharp smell after hard use or slipping comes from overheated friction material.
- Hard shifting or grinding: if the clutch does not fully release, gears grind or are hard to select. This can also be a hydraulic problem.
- Chatter or judder: shaking as the clutch engages from a stop can point to a worn disc, a glazed flywheel or contamination.
- Noise when you press the pedal: a whir or squeal that changes when you press the pedal often comes from the release bearing.
- Soft, spongy or sticking pedal: usually the hydraulic side (master or slave cylinder, or air in the fluid), but it stops the clutch working properly.
Clutch slipping: what to check first
Rule out the simple causes before replacing parts: check the clutch fluid level and look for leaks, and on cars with an adjustable linkage confirm it is set correctly. Oil from a leaking rear main seal or transmission seal can contaminate a clutch and make it slip even with plenty of material left. If the clutch is simply worn, it needs to be replaced; a slipping clutch heats the flywheel and gets worse quickly.
How long does a clutch last?
There is no fixed interval. A clutch that spends most of its life on the highway can outlast the car, while one used in heavy traffic, for towing or for launches wears much faster. Habits that shorten clutch life include resting a foot on the pedal, holding the car on a hill with the clutch, and slipping it at high engine speed. Adding power also matters: a factory clutch is sized for factory torque, and extra power can make it slip long before it is worn out.
Upgrading when you replace it
If the car has more power than stock or will see track use, a performance clutch with a higher torque capacity is worth considering. The ACT kits we carry list their capacity, for example the WRX HD kit at 449 ft-lbs (39% over the factory clutch), the STI HD kit at 515 ft-lbs and the Civic Si HD kit at 363 ft-lbs (63% over the factory clutch). Higher clamp load can mean a heavier pedal: ACT describes its Heavy Duty kits as light to moderate effort and its Xtreme kit as moderate to heavy.
Sprung vs unsprung clutch discs
A sprung disc has small springs in its hub that soften engagement and absorb driveline shock, which makes it smoother and quieter on the street. An unsprung (solid hub) disc is lighter but harsher and more likely to chatter, so it is mostly used in racing. The ACT kits listed here all use sprung street discs.
Replacing a clutch: what to replace with it
- Replace the release bearing and pilot bearing; much of the labor is already done and many kits include them.
- Resurface or replace the flywheel. Several ACT kits must be used with the ACT flywheel supplied in the box, as each listing states.
- Inspect the rear main seal and the clutch hydraulics while everything is apart.
Clutch break-in
A new clutch needs time for the disc and flywheel to bed in before it reaches full holding power. Follow the break-in procedure in the kit’s instructions; most call for a few hundred miles of normal driving with smooth engagement, avoiding hard launches and high-RPM engagement during that period.
Clutch kits we carry
ACT kits for the Subaru WRX, the WRX STI, the 2008-2015 Evo X and the Honda Civic Si and 1.5T, from $833.00. See every kit on the ACT page, or by car: WRX and STI parts, Evo parts and Civic Si parts.
More guides: clutch slipping · clutch chatter · how long a clutch lasts · stage 1 vs stage 2 clutch · car won’t go into gear · dual mass vs single mass flywheel · clutch master cylinder symptoms · organic vs ceramic clutch discs · clutch break-in.
Trouble codes: P0704 Clutch Switch Input · all OBD2 codes.
Shipping is a flat $80.00 per order to US addresses, with 15-day free returns. Questions? Ask a parts specialist.