The most common signs of a bad transmission are slipping (engine speed rising without the vehicle speeding up), delayed engagement when shifting into drive or reverse, harsh or erratic shifts, a burning smell, red fluid leaks, whining or grinding noises and a check engine or transmission warning light. Many of these can also come from low fluid, a sensor or a solenoid, so check the fluid and read the codes before assuming the transmission is finished.
Signs of a bad transmission
| Sign | What it can mean |
|---|---|
| Slipping or flaring between gears | Low fluid, worn clutches or bands; see transmission slipping |
| Delay into drive or reverse | Low fluid, worn seals or pump; see delayed engagement |
| Harsh, late or erratic shifts | Fluid, pressure control or electrical faults; see shifting hard |
| Stuck in one gear | Limp mode from a fault; see transmission won’t shift |
| Whining, grinding or clunking | Pump, bearings, gears or mounts; see transmission noise |
| Burning smell | Overheated fluid; see burning smell from car |
| Red fluid under the vehicle | A leak; see transmission fluid leak |
| Warning light | Stored transmission codes such as P0700 |
How to tell if the transmission is bad while driving
- Watch the tachometer: engine speed jumping up without acceleration is slipping.
- Feel for shifts that bang, flare or come at odd speeds.
- Note whether problems are worse when hot, cold or under load.
- Listen for whines that change with speed or gear.
Transmission or torque converter?
A shudder like driving over rumble strips at steady light-throttle speeds, slipping only at cruise, or overheating with otherwise normal shifts often points to the torque converter; slipping between specific gears, harsh shifts and delayed engagement point to the transmission itself. See bad torque converter symptoms and torque converter shudder.
Automatic vs manual
On a manual, grinding gears, a clutch that slips or will not release, and popping out of gear are the typical signs; see signs of a bad clutch. Many manual problems are clutch problems rather than gearbox failures.
What to check first
- Fluid level, color and smell; see how to check transmission fluid and fluid color.
- Codes from a scan tool that reads the transmission; see how to use an OBD2 scanner.
- Battery voltage, wiring and sensors; see solenoid symptoms.
When it really is the transmission
Burnt fluid with friction material or metal in the pan, slipping in several gears and gear ratio codes usually mean internal wear. Compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, and find your unit by code on our transmissions page.
More guides: car won’t move in drive · car rolls in park · car jerks when shifting · transmission or torque converter? · engine or transmission problem? · what the metal on the pan magnet means · transmission line pressure.
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