Torque converter


Torque converter problems are sometimes misinterpreted as symptoms of a failing transmission.

In a nutshell, a torque converter is a fluid coupling that transfers torque from the engine to the transmission. It is mounted between the engine and transmission, bolted directly to a ‘flex plate’ which is spun by the crankshaft. 

  • Transmission to delay a shift, or slip out of gear.
  • Overheating – Low fluid levels or a malfunctioning solenoid can also cause a transmission to overheat.
  • When driving at a lower speed, around 30 to 45 miles per hour, you may feel a shudder, as if you’re driving over bumps.
  • Strange sounds – Any foreign sounds such as clicking or a revving noise
  • Your car doesn’t accelerate properly 
  • Illumination of the Check Engine Light
  • Engine stalling
  • Clanking or rattling type noise as engine speed changes
  • Abnormal vibration
  • Lack of power
  • Transmission fluid leak
  • Abnormal noise when the starter is engaged 
  • However, diagnosing the cause of a transmission issue isn’t easy. In many cases, the torque converter will not actually be the source of the problem (you might just have a fluid leak!).
  • Bad torque converter needle bearings
  • Damaged torque converter seals
  • Worn Torque Converter Clutch – Automatic transmissions have a number of clutches located throughout the assembly. 
  • In addition to transferring the power from the engine to the driveline, the torque convertor will “slip” at idle, allowing the engine to remain running while the drive wheels are stopped
  • To increase fuel economy, all modern vehicles have an electronically controlled clutch inside the torque convertor which “locks” the torque converter at freeway speeds, eliminating any internal slippage
  • If the torque converter clutch does not disengage at idle, the engine may stall
  • Simply draining the transmission, or removing the pan and filter, does not drain the old fluid from the torque convertor. A fluid exchange procedure must be performed to remove and replace all of the fluid in the transmission, torque convertor, and cooler system.
  • The torque convertor should be replaced when the transmission is overhauled or replaced 

References