Stop drivingred light
Automatic Gearbox Temperature Warning
The automatic transmission is overheating — stop before permanent damage occurs.
What it means
A red icon of a gear with a thermometer, sometimes with the word AT or TEMP. The automatic gearbox oil has exceeded its safe temperature. Automatic transmissions rely on fluid for both lubrication and hydraulic pressure — overheating degrades the fluid rapidly and can burn out clutches, torque converters and seals.
What to do
- 1Pull over safely as soon as possible and switch off the engine. Allow 20–30 minutes for the gearbox to cool.
- 2Check the gearbox fluid level once cool — but only if you know how (some are sealed for life).
- 3Avoid towing, hard acceleration and stop-start traffic until the cause is found.
- 4If the light comes on regularly, get the gearbox inspected immediately — continued overheating will destroy it.
Likely causes
- •Towing heavy loads or driving in mountains / stop-start traffic in hot weather
- •Low or degraded gearbox fluid
- •Faulty gearbox oil cooler or cooler lines
- •Internal clutch slip generating excess heat
- •Blocked radiator cooling passages (some gearboxes share the engine radiator)
Rough UK cost
Fluid change: £150–£350. Cooler repair: £200–£500. Gearbox rebuild: £2,000–£5,000+. Replacement: £3,000–£8,000.
Prices are a guide only — always get a written quote before any work.
Heads up: Carautonomy is for general guidance only. If your car is behaving oddly or any red light is on, get it inspected by a qualified mechanic.