A bad torque converter interferes with the transfer of power from the engine to the transmission of a vehicle. It causes transmission overheating, slipping and shuddering and poor fuel economy. Vehicle owners sometimes think their transmission is bad when the real problem is the torque converter.
With a bad torque converter, a vehicle must work harder to maintain the same speed. The engine operates at a higher number of revolutions per minute, decreasing fuel economy and the pressure of the transmission fluid and increasing the amount of heat the system generates.
When a vehicle experiences torque converter problems, it often starts to shudder at speeds between 30 and 45 miles per hour. The shudder feels like the car is driving over a rough road, even though it is on a smooth surface.
Damaged transmissions and torque converter clutches produce large amounts of black debris in the transmission fluid. Change the fluid, and check it regularly to determine if the problem continues.
A speed-stall test helps to determine if a vehicle is experiencing a torque converter problem. Always check with the vehicle manufacturer before beginning this test because it can damage the transmissions of some vehicles. Avoid performing the speed-stall test on vehicles with anti-lock brakes to prevent damaging them. This test illuminates the check engine light on vehicles with electronic monitoring systems.