While driving car it lost all gears Pulled over idled fine but will not shift into any got back from having a new water pump main belt broke and damaged the crank position sensor on WA?

The broken serpentine belt and damaged crank position sensor are very likely the cause of your car not shifting gears. The crank position sensor is crucial for the transmission's computer to know engine speed and position, which is essential for proper gear selection and shifting. Without this information, the transmission control module (TCM) may go into a "limp mode" or simply refuse to shift.

Here's why:

* Automatic Transmission: Most automatic transmissions rely heavily on the engine's speed and position signals (provided by the crank position sensor) to determine the appropriate gear. A faulty sensor will disrupt this communication, preventing gear changes.

* Manual Transmission (Less Likely): While less common, some modern manual transmissions also utilize sensors for various functions. A damaged sensor might interfere with clutch engagement or other electronically controlled aspects.

What to do:

1. Get the crank position sensor replaced: This is the most likely culprit. A mechanic can easily replace this sensor.

2. Check the transmission fluid: While unlikely to be the *sole* cause, if the belt broke and spun for a while, it's possible some debris got into the transmission. Check the fluid level and condition. If it's low, dark, or smells burnt, further investigation is needed.

3. Have the car properly diagnosed: Even after replacing the crank position sensor, a professional mechanic should scan your car's computer system for any diagnostic trouble codes (DTCs). This will help determine if there's any other damage. It's possible the prolonged lack of power from the belt breaking may have damaged other components.

Important Note: Driving a car that won't shift gears is dangerous. Do not attempt to drive it until it's been properly repaired. Have it towed to a mechanic.