The torque converter sits between the engine and an automatic transmission. When it starts to fail the symptoms can look like a transmission problem, so it helps to know what it does and what the warning signs are.
What does a torque converter do?
A torque converter is a fluid coupling. The engine spins an impeller that drives transmission fluid against a turbine connected to the transmission, so the engine can idle while the vehicle is stopped in gear. At low speed it also multiplies torque for stronger acceleration. Most modern converters have a lock-up clutch (the torque converter clutch, or TCC) that locks the engine and transmission together at cruising speed for better fuel economy.
Bad torque converter symptoms
- Shudder: a vibration like driving over rumble strips, often at steady speeds when the lock-up clutch engages.
- Slipping: engine rpm rises without a matching increase in speed.
- Overheating: a failing converter generates heat and can trigger a transmission temperature warning.
- Delayed or no engagement: the vehicle is slow to move, or does not move, when put in gear.
- Noises: whining or grinding that changes with engine speed.
- Contaminated fluid: dark fluid or debris in the transmission fluid.
- Trouble codes: a check engine light with torque converter clutch codes such as P0741.
Several of these symptoms are shared with low fluid, solenoid faults and internal transmission wear, so have the transmission diagnosed before replacing parts. If debris from a failed converter has circulated through the transmission, replacing the transmission and converter together is the safer repair.
Can you replace just the torque converter?
Yes, if the transmission itself is healthy and the fluid shows no metal debris. The converter sits inside the bellhousing, so the transmission still has to come out to reach it, which is why most of the cost of a converter job is labor. While it is out, it makes sense to replace the transmission front pump seal, inspect the flexplate, and flush or replace the transmission cooler so old debris does not reach the new converter.
What a converter replacement involves
- Remove the driveshaft (and on 4WD trucks, often the transfer case), cooler lines, wiring and crossmember.
- Unbolt the converter from the flexplate and lower the transmission.
- Fit the new converter, making sure it is fully seated on the pump drive so the pump is not damaged on startup.
- Reinstall, refill with the specified fluid and check the level at temperature.
More on how converters work: what does a torque converter do?
Torque converters in stock
Transmissions supplied with a torque converter
50 of our replacement transmissions come with a matched torque converter. See transmissions by code.
See also: torque converter shudder · what is a stall converter? · transmission slipping: signs and causes · what transmission do I have?
Related guides: car jerks when accelerating · whining noise when accelerating.
More guides: transmission noise · transmission or torque converter? · car won’t move in drive · torque converter lockup · bad transmission or torque converter? · torque converter replacement · how long a torque converter lasts · bad flex plate symptoms · bad transmission pump symptoms.
Trouble codes: P0741 Torque Converter Clutch Stuck Off · P0740 Torque Converter Clutch Circuit · P0742 TCC Stuck On · P0743 TCC Circuit Electrical · all OBD2 codes.
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