Possible causes of impacts when shifting gears in a Toyota automatic transmission:
* Faulty Transmission Control Unit (TCU): A faulty TCU can cause improper shift control, causing knocks.
* Worn or dirty solenoids: Solenoids control the flow of fluid into the automatic transmission, wear or contamination can impair their operation, leading to knocks.
*Low automatic transmission fluid level: Insufficient fluid level can cause slippage and shock when shifting gears.
* Dirty or clogged automatic transmission fluid: Contaminated transmission fluid can block fluid flow, disrupting solenoids and causing knocks.
* Worn or damaged friction discs: Friction discs transmit power between gears, wear or damage can cause slippage and shock.
* Faults in the hydraulic system: Faults in the hydraulic unit, pump or other components can affect fluid flow and cause shock.
*Faulty Speed Sensor: A faulty speed sensor may provide incorrect data to the TCU, resulting in incorrect gear shifts.
*Wiring Problems: Faulty wiring can interfere with communication between the TCU and other automatic transmission components, causing shifting problems.
Solution:
* Check the automatic transmission fluid level and add it if necessary.
* Replace worn or dirty solenoids.
* Flush or replace contaminated automatic transmission fluid.
* Check the friction discs for wear or damage and replace them if necessary.
* Eliminate faults in the hydraulic system.
* Replace the faulty speed sensor.
* Eliminate faults in electrical wiring.
*If the problem persists, diagnostic testing using an OBD-II scanner and repair of the transmission control unit (TCU) or other faulty components may be required.