CVT Gearbox & Transmission Repair

A CVT (continuously variable transmission) is an automatic gearbox with no fixed gears. Instead, two cone-shaped pulleys joined by a steel belt or chain change size continuously, giving a smooth, stepless range of ratios that keeps the engine at its most efficient speed. You won't feel gear changes, just a steady build of speed.

Yes, for most drivers. CVT gearboxes are smooth, fuel-efficient and generally reliable when the fluid is kept in good condition, which is why they're common in small cars, SUVs and hybrids. They're less suited to heavy towing or hard driving, and they're more sensitive to fluid condition and overheating than a conventional automatic. Most CVT faults can be repaired without replacing the whole gearbox.

A torque converter automatic uses a fluid coupling and a set of fixed gears that it changes between. A DSG, or dual-clutch gearbox, uses two clutches to pre-select fixed gears for very fast changes. A CVT has no fixed gears at all, using pulleys and a belt or chain to vary the ratio continuously. Each has different typical faults, so identifying which one your car has is the first step of any diagnosis.

Common CVT gearbox problems include whining or droning that rises with speed, shudder when pulling away, revs flaring without acceleration, slow engagement of Drive or Reverse, limp mode and a transmission warning light. The usual causes are old, low or incorrect fluid, a worn belt or chain, pulley and bearing wear, valve body or solenoid faults, and control unit failures.

A whining or droning CVT usually points to worn pulley faces or bearings, the most common source of CVT noise. Grinding or rattling can mean a worn belt or chain, or more advanced internal wear, and low or degraded fluid makes noise worse. Get it diagnosed early, as replacing worn bearings is usually far cheaper than a rebuild.

When a CVT revs but the car doesn't accelerate, the drive is slipping. The usual causes are old, low or incorrect fluid that can no longer grip the belt or chain, a stretched or worn belt or chain, or valve body and step motor faults that stop the pulleys holding pressure. Slipping that's worse when the gearbox is hot often points to degraded fluid.

A CVT that judders when pulling away or creeping in traffic usually has wear in the torque converter or wet clutch pack that takes up drive from a standstill. A worn belt or chain, or degraded fluid, can cause judder when accelerating. A diagnostic will confirm which it is before any parts are replaced.

Yes. Many CVT faults can be fixed with a targeted repair, such as replacing a worn belt or chain, repairing pulleys and bearings, fixing the valve body, step motor or solenoids, repairing the control unit, or sealing a fluid leak and refilling with the correct CVT fluid. After any repair the CVT is recalibrated and road tested. Service4Service only recommends a rebuild or replacement when a targeted repair won't fix the fault.

Yes. A CVT rebuild, also called reconditioning or refurbishment, involves a full strip-down, inspection of every component against manufacturer tolerances, and renewal of worn internals such as the belt or chain, pulleys and bearings. Where a rebuild isn't the sensible route, Service4Service can supply and fit a reconditioned CVT unit.

Many CVT gearboxes last well over 100,000 miles, but lifespan depends on the CVT design, how the car is driven and whether the fluid has been kept in good condition. Towing, hard acceleration and long periods of overheating shorten it. Faults caught early are usually repairable without replacing the gearbox.

The cost of a CVT gearbox repair depends on the fault, the CVT design, the parts and labour needed, and whether a targeted repair, rebuild or reconditioned replacement is required. Targeted repairs are usually far cheaper than a replacement gearbox. Service4Service runs a full diagnostic first and gives you a confirmed price to approve before any work begins.

Service4Service uses OEM (original equipment manufacturer) or manufacturer warranty-approved parts, meaning parts made by or for the vehicle maker, and work is carried out in a way that protects your existing manufacturer's warranty. If you have a warranty policy, tell us at the start and we can help liaise with the provider. Every repair is guaranteed for 12 months or 12,000 miles.