A slipping clutch lets engine speed rise without the car accelerating to match, because the clutch disc can no longer hold the engine’s torque. It shows up first in higher gears under load, such as accelerating hard in fourth or climbing a hill, often with a burning smell. Worn friction material is the usual cause, but oil contamination, a weak pressure plate, a hydraulic fault that keeps the clutch partly released, or more power than the clutch was built for can all cause it.
Clutch slipping symptoms
- Engine speed flares up when you accelerate, especially in third, fourth and higher gears
- A burning smell after hard acceleration or hill starts
- The clutch engages higher in the pedal travel than it used to
- Poor acceleration and worse fuel economy
How to check for clutch slip
On a safe, empty road, drive at low speed in a high gear (for example 30 mph in fourth) and press the accelerator firmly. If engine speed jumps while road speed barely changes, the clutch is slipping. Do not repeat the test many times; it heats and wears the clutch further.
Common causes
| Cause | Clues |
|---|---|
| Worn clutch disc | High mileage, gradual onset, high engagement point |
| Oil on the disc | Sudden slip, oil leak from the rear main seal or transmission input seal; see oil leaks |
| Weak or overheated pressure plate | Slip after heavy use, discolored parts |
| Hydraulic or cable fault | Pedal not returning fully or clutch not fully engaging |
| Added power | Slips only at full throttle after engine upgrades |
Clutch slipping in first gear vs high rpm
Slip in first is less common because first gear multiplies torque the most and the clutch spends little time under full load there; slip that appears first in high gears at high rpm is the classic worn-clutch pattern. Slip only at the top of the rev range after adding power usually means the clutch’s holding capacity is exceeded.
How long will a slipping clutch last?
Not long. Once slipping starts, heat glazes the friction surfaces and the slip gets worse quickly, and continued slipping can damage the flywheel; see how long does a clutch last.
Fixing a slipping clutch
The fix is a new clutch kit, with the flywheel resurfaced or replaced, and the source of any oil leak repaired first. If the car has more power than stock, choose a clutch rated for it; see stage 1 vs stage 2 clutch and signs of a bad clutch. Our ACT kits include the ACT HD Performance Street Sprung kit for the WRX ($1,204.00); see all on the ACT clutches page.
More guides: car won’t go into gear · clutch master cylinder symptoms · organic vs ceramic clutch discs · clutch break-in · ACT Heavy Duty vs Xtreme.
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