Signs of a malfunctioning Toyota automatic transmission torque converter:
Sticking and slipping:
* Increased acceleration time
* Slipping when changing gears
* Rough gear shifting
Noise and vibration:
*Buzzing or knocking sound when accelerating
* Vibration at certain speeds
Fluid leaks:
*Red ATF leaking from under the gearbox
* Insufficient ATF fluid level
Burnt or burning smell:
* Burnt or burning smell coming from under the gearbox
* ATF overheating
Other signs:
* Poor acceleration or difficulty downshifting
* Difficulty reversing
* Complete loss of transmission
Possible causes of torque converter malfunction:
* Wear or damage to blades or guide vanes
* Clogged torque converter filter
* Insufficient ATF fluid level
* ATF overheating
*Friction material defect
* Deformation or damage to the torque converter housing