Mechanical reasons:
* Wear or damage to valve body parts such as spools, plungers or springs
* Accumulation of debris or metal particles in the valve body
*Damage or clogging of valve body channels
* Incorrectly adjusted or worn pressure modulator
Electrical reasons:
* Malfunction of valve body solenoids
*Damage or corrosion of electrical connectors and wiring
* Malfunction of the electronic control unit (ECU)
Hydraulic reasons:
* Insufficient pressure in the hydraulic system
* Fluid leaks from the valve body
* Air or foam in hydraulic fluid
* Worn or dirty automatic transmission filter
Other reasons:
* Transmission fluid overheating
* Using poor quality or unsuitable transmission fluid
* Sharp acceleration or braking, which can lead to water hammer