Symptom
Shudder at steady cruising speed
A vibration or judder felt at a constant speed, often described as driving over rumble strips, that appears at a particular speed and disappears if you accelerate or lift off. Characteristically a torque converter lock-up clutch that is engaging but slipping rather than gripping cleanly. Distinct from a wheel balance vibration, which varies smoothly with road speed instead of arriving and leaving at one point — and distinct from a misfire, which is felt in the engine rather than through the driveline.
Also described as: shudder at speed, judder at cruise, rumble strip feeling, vibration at steady speed, torque converter shudder, shuddering when cruising, chugging at motorway speed, chugging at freeway speed, لرزش در سرعت ثابت, ویبره در سرعت یکنواخت, vibra a velocidad constante, tirones a velocidad constante, tembleque en carretera, رجة على سرعة ثابتة, اهتزاز على الطريق السريع, نقزات على سرعة ثابتة
Some causes mean you should stop driving
1 of the 20 codes that produce this symptom indicate a fault where continuing to drive risks damage or is unsafe. If the symptom is sudden or severe, treat it as one of those until a scan says otherwise.
What this usually means
A vibration that arrives at one speed and leaves the moment you touch the throttle is a torque converter lock-up clutch slipping, and the specificity of that comes from the way the clutch is used. It engages to remove slip at cruise, and it is applied progressively rather than as a switch — so a clutch that grips imperfectly chatters at exactly the point where it is asked to hold a small, steady torque. English references describe the sensation as driving over rumble strips and place it typically between about 60 and 80 km/h under light load, which matches where lock-up is commanded.
Three tests separate it from everything else and each takes seconds. Touch the brake pedal lightly: lock-up releases the instant the brake switch closes, so a shudder that vanishes at the first touch of the pedal is the clutch. Press the throttle firmly or lift off completely: both unlock, so the shudder should disappear either way. And watch the rev counter — a slipping clutch shows a small fluctuation in engine speed while the throttle position has not moved.
Fluid condition is the cause far more often than the clutch is worn out. Degraded or contaminated fluid loses the friction characteristics the clutch's controlled slip depends on, and dark or burnt-smelling fluid confirms it in a glance. Caught early, a service to the manufacturer's exact specification frequently resolves it entirely — and the specification is not negotiable, because the friction modifier in the correct fluid is precisely what the clutch is calibrated against.
Rule out the two impostors before touching the transmission. A wheel balance vibration varies smoothly with road speed rather than arriving and departing at one point; a misfire is felt in the engine and does not care about brake or throttle position. Both are distinguished on the road, not on a ramp.
Working through it
| What you find | Likely cause | How to confirm it | What fixes it |
|---|---|---|---|
| Shudder disappears the instant the brake pedal is touched | Torque converter lock-up clutch slipping — the brake switch releases it | This is the decisive test and needs no equipment. Corroborate by pressing the throttle firmly and by lifting off: both unlock, and both should stop it. | Check fluid condition first, then service to the exact specified fluid. The clutch itself is less often the failure than the fluid is. |
| Small engine speed fluctuation with the throttle held steady | The clutch slipping intermittently rather than holding | Watch the rev counter or live engine speed at a constant throttle. Live lock-up status alongside it confirms the timing. | Fluid service to specification. Reassess afterwards before committing to converter replacement. |
| Transmission fluid dark or smelling burnt | Degraded fluid — the friction characteristics the controlled slip depends on have gone | Inspect against a fresh sample. Colour and smell are both diagnostic and cost nothing to check. | Service to the manufacturer's exact specification. The wrong fluid, however good, causes this fault rather than curing it. |
| Vibration varies smoothly with road speed and ignores the brake and throttle | Not the transmission — wheel balance, a bent rim, a tyre with a broken belt, or a driveshaft | The absence of a brake and throttle response is the discriminator. Confirm by balancing and by inspecting the tyres for irregular wear. | Balance or renew the wheel or tyre. Do not service the transmission for this. |
| Felt through the engine rather than the floor, unaffected by brake or throttle | A misfire under light load rather than a driveline fault | Read misfire counters while cruising at the speed it happens. A light-load misfire is easy to miss on a static test. | Diagnose the misfire on its own findings — ignition, injector or a lean cylinder. |
| Shudder plus stalling as the car comes to a stop | The same lock-up clutch failing both ways — slipping when engaged, dragging when it should release | Treat as one fault. Fluid condition is the common cause of both and is the first thing to look at. | Service the fluid to specification and reassess both symptoms together. |
-
Shudder disappears the instant the brake pedal is touched
- Likely cause
- Torque converter lock-up clutch slipping — the brake switch releases it
- How to confirm it
- This is the decisive test and needs no equipment. Corroborate by pressing the throttle firmly and by lifting off: both unlock, and both should stop it.
- What fixes it
- Check fluid condition first, then service to the exact specified fluid. The clutch itself is less often the failure than the fluid is.
-
Small engine speed fluctuation with the throttle held steady
- Likely cause
- The clutch slipping intermittently rather than holding
- How to confirm it
- Watch the rev counter or live engine speed at a constant throttle. Live lock-up status alongside it confirms the timing.
- What fixes it
- Fluid service to specification. Reassess afterwards before committing to converter replacement.
-
Transmission fluid dark or smelling burnt
- Likely cause
- Degraded fluid — the friction characteristics the controlled slip depends on have gone
- How to confirm it
- Inspect against a fresh sample. Colour and smell are both diagnostic and cost nothing to check.
- What fixes it
- Service to the manufacturer's exact specification. The wrong fluid, however good, causes this fault rather than curing it.
-
Vibration varies smoothly with road speed and ignores the brake and throttle
- Likely cause
- Not the transmission — wheel balance, a bent rim, a tyre with a broken belt, or a driveshaft
- How to confirm it
- The absence of a brake and throttle response is the discriminator. Confirm by balancing and by inspecting the tyres for irregular wear.
- What fixes it
- Balance or renew the wheel or tyre. Do not service the transmission for this.
-
Felt through the engine rather than the floor, unaffected by brake or throttle
- Likely cause
- A misfire under light load rather than a driveline fault
- How to confirm it
- Read misfire counters while cruising at the speed it happens. A light-load misfire is easy to miss on a static test.
- What fixes it
- Diagnose the misfire on its own findings — ignition, injector or a lean cylinder.
-
Shudder plus stalling as the car comes to a stop
- Likely cause
- The same lock-up clutch failing both ways — slipping when engaged, dragging when it should release
- How to confirm it
- Treat as one fault. Fluid condition is the common cause of both and is the first thing to look at.
- What fixes it
- Service the fluid to specification and reassess both symptoms together.
Codes that produce this symptom (20)
Listed with the codes that most typically present this way first — the likeliest place to start.
- P0740 Torque Converter Clutch Circuit/Open Typical of this code Moderate
- P0741 Torque Converter Clutch Circuit Performance/Stuck Off Typical of this code Moderate
- P0742 Torque Converter Clutch Circuit Stuck On Typical of this code High
- P0743 Torque Converter Clutch Circuit Electrical Typical of this code Moderate
- P0744 Torque Converter Clutch Circuit Intermittent Typical of this code Moderate
- P07BF Input/Turbine Shaft Speed Sensor A Circuit Low Typical of this code Moderate
- P2756 Torque Converter Clutch Pressure Control Solenoid Typical of this code Moderate
- P2757 Torque Converter Clutch Pressure Control Solenoid Control Circuit Performance/Stuck Off Typical of this code Moderate
- P2758 Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On Typical of this code Stop driving High
- P2759 Torque Converter Clutch Pressure Control Solenoid Control Circuit Electrical Typical of this code Moderate
- P2760 Torque Converter Clutch Pressure Control Solenoid Control Circuit Intermittent Typical of this code Moderate
- P2761 Torque Converter Clutch Pressure Control Solenoid Control Circuit/Open Typical of this code Moderate
- P2762 Torque Converter Clutch Pressure Control Solenoid Control Circuit Range/Performance Typical of this code Moderate
- P2763 Torque Converter Clutch Pressure Control Solenoid Control Circuit High Typical of this code Moderate
- P2764 Torque Converter Clutch Pressure Control Solenoid Control Circuit Low Typical of this code Moderate
- P2769 Torque Converter Clutch Circuit Low Typical of this code Moderate
- P2770 Torque Converter Clutch Circuit High Typical of this code Moderate
- P0726 Engine Speed Input Circuit Range/Performance High
- P0734 Gear 4 Incorrect Ratio High
- P0783 3-4 Shift Malfunction High
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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