* Dirty transmission fluid. Dirty transmission fluid can also cause the transmission to slip and not shift properly.
* Worn transmission components. Worn transmission components, such as gears, clutches, and bands, can also cause the transmission to not shift properly.
* Faulty transmission control module. The transmission control module (TCM) is responsible for controlling the transmission. If the TCM is faulty, it can cause the transmission to not shift properly.
* Faulty shift solenoid. The shift solenoid is responsible for engaging and disengaging the gears in the transmission. If the shift solenoid is faulty, it can cause the transmission to not shift properly.
* Faulty torque converter. The torque converter is responsible for transferring power from the engine to the transmission. If the torque converter is faulty, it can cause the transmission to not shift properly.
* Vacuum leak A vacuum leak can cause a number of drivability problems, including delayed or erratic shifting.
