Possible causes of automatic transmission jolts when braking on a Kia Ceed:
1. Wear or contamination of transmission fluid:
* Over time, transmission fluid loses its lubricating and cooling properties, which leads to increased friction and jerking.
* Contamination of the fluid with metal shavings or other particles can lead to clogging of the valve body and gear shifting problems.
2. Malfunction of solenoids or automatic transmission valves:
* Solenoids and valves are responsible for shifting gears. If they are faulty or sticky, it can lead to harsh shifts and jerks.
3. Wear of friction discs and bands:
* Friction discs and bands are subject to abrasion during operation. Excessive wear can lead to slippage or over-adhesion, which causes shock.
4. Torque converter malfunction:
* The torque converter connects the engine and automatic transmission. If it is faulty, it can cause shifting problems and jerking.
5. Malfunction of the automatic transmission electronic control unit (ECU):
* The ECU is responsible for controlling the operation of the automatic transmission. A malfunction of the ECU can lead to incorrect operation of the gearbox and jerks.
6. Problems with sensors:
* Speed, crankshaft position and throttle position sensors transmit information to the ECU to control the automatic transmission. Faulty sensors can result in incorrect gear shifting and jerking.
How to fix the problem:
* Check and, if necessary, replace transmission fluid.
* Diagnose and replace faulty automatic transmission solenoids or valves.
* Replace worn friction discs and bands.
* Check and, if necessary, repair the torque converter.
* Check and, if necessary, replace the automatic transmission ECU.
* Check and replace faulty sensors.
It is recommended that you contact a qualified mechanic for accurate diagnosis and repair. Ignoring shocks can lead to more serious problems and costly repairs.