Possible reasons:
Mechanical problems:
* Wear of friction clutches
* Malfunction of solenoids
* Oil filter clogged
*Low transmission fluid level
* Worn gears
Electrical faults:
* Malfunction of the throttle position sensor
*Speed sensor malfunction
* Problem with the automatic transmission electronic control unit
Hydraulic problems:
*Transmission fluid leak
* Transmission fluid contamination
* Oil pump malfunction
Possible solutions:
Self-diagnosis:
* Check the level and condition of the transmission fluid.
* Check for transmission fluid leaks.
* Inspect the transmission pan for signs of wear or dirt.
Professional diagnostics and repair:
* Scan trouble codes using diagnostic scanner
* Checking the pressure in the automatic transmission
* Dismantling and disassembling of automatic transmission for inspection and repair
* Replacement of worn clutches, solenoids, gears and other components
* Cleaning the oil filter and replacing transmission fluid
Prevention:
* Regular replacement of transmission fluid and filter
* Avoiding aggressive driving
* Use of original or manufacturer-recommended spare parts
* Regular inspection of the automatic transmission by a mechanic