Buying guide · 7 min read

Automatic gearbox warning signs to check on a test drive

Gearbox repairs are among the most expensive bills a used car can land you with, often running into thousands. The good news is that most failing gearboxes give clear warning signs on a proper test drive, if you know what to feel and listen for.

Written by the VehicleFaults Research Team · reviewed October 2026

1. Know which type of automatic it is

Torque converter automatics, smooth and generally durable when the fluid is changed
CVT gearboxes, no fixed gears, can whine or judder when worn
Dual-clutch gearboxes (DSG, DCT, EDC, Powershift), quick shifts but can judder at low speed when the clutches wear
Automated manuals, jerky by design but should not slip

2. Warning signs on the test drive

Delay when you select Drive or Reverse
Revs flaring between gears, a sign of slip
Harsh thumps or clunks on changes, especially when cold
Judder or shudder pulling away gently in traffic
Whining or droning that rises with speed
Gearbox warning light or the car going into limp mode

3. How to test it properly

Start from cold, faults are often worst before the fluid warms up
Pull away gently several times as if in traffic
Accelerate firmly from 30 to 60 mph and feel for slip
Try reverse up a slight slope
Use manual mode, if fitted, and check every gear engages

4. Service history matters

Many automatics are sold as sealed for life, but fluid changes at around 40,000 to 60,000 miles greatly improve their lifespan. A receipt for a gearbox fluid change is a good sign, and dual-clutch gearboxes often need a specific service.

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Frequently asked questions

How much does an automatic gearbox repair cost?

A fluid service is usually a few hundred pounds, but a rebuild or replacement can run from about £1,500 to over £4,000 depending on the car.

Is a little judder normal on a dual-clutch gearbox?

A slight hesitation can be normal, but a clear shudder when pulling away is a wear sign and should be checked before you buy.

Should I avoid CVT gearboxes?

Not all of them. Toyota and Honda hybrid systems are very reliable. Some other CVTs have a poorer record, so check the specific model on our fault pages.