How a Continuously Variable Transmission (CVT) Works
A continuously variable transmission has no fixed gears. Instead it uses two cone-shaped pulleys connected by a steel belt or chain, changing their diameters to provide an infinite range of ratios and keep the engine at its most efficient speed.
Animated: how a Continuously Variable Transmission (CVT) actually works
🔧 How It Works, Step by Step
1
Two variable pulleys hold a belt
A drive pulley and a driven pulley each split into cones that move closer or farther apart to change effective diameter.
2
Pulley width changes the ratio
As one pulley narrows and the other widens, the belt rides at different diameters, smoothly varying the gear ratio.
3
Hydraulic pressure controls the pulleys
A pump and valve body squeeze the pulley halves with precise pressure to hold and change ratios.
4
The engine stays in its sweet spot
The system keeps engine RPM near peak efficiency or power while road speed climbs, giving seamless acceleration.
🧩 The Key Parts
Drive and driven pulleys
Adjustable cone pairs that change diameter to vary the ratio.
Steel belt or chain
Transfers power between the two pulleys at any ratio.
Hydraulic control unit
Applies pressure to move the pulley halves and set the ratio.
Torque converter or clutch
Couples the engine to the CVT and allows idling in gear.
CVT control module
Commands ratio changes based on throttle and speed.
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🩺 Signs of a Failing Continuously Variable Transmission (CVT)
Shuddering or juddering during light acceleration
Whining or high-pitched noise that rises with speed
Delayed acceleration or a rubber-band feel
Overheating warning during hard or prolonged driving
Slipping where RPM flares without matching speed
⚠️ Common Problems
Belt and pulley wear
The steel belt and pulley surfaces wear over time, causing slipping, shuddering, and eventual failure that often requires a full unit.
Overheating
CVTs are heat-sensitive, and inadequate cooling or old fluid can cause failure, especially with towing or heavy loads.
Degraded CVT fluid
CVTs need specific fluid, and worn or wrong fluid leads to shudder, slipping, and internal damage.
💰 Cost to Fix
$3,000-$5,000typical range to repair or replace, parts and labor
❓ FAQ
Why does my CVT feel like a rubber band?
The rubber-band sensation is normal CVT behavior where RPM rises before speed catches up, though excessive slipping can signal wear.
How long does a CVT last?
A well-maintained CVT can last well over 100,000 miles, but they are sensitive to fluid condition and heat, so regular service matters.
Can a CVT be repaired or must it be replaced?
Minor issues like fluid or a valve body can be fixed, but worn belts and pulleys often mean replacing the whole assembly.