Following the installation of a new XY shifter assembly, which calibration should be prioritized?

When a new XY shifter assembly is installed in a vehicle, the calibration of the shifter itself should be prioritized. This is crucial because the shifter directly impacts the transmission's operation, ensuring that gear selection is accurate and responsive. Proper shifter calibration allows for precise engagement and disengagement of gears, which is essential for the vehicle’s performance and longevity. Without this calibration, you might experience difficulties in shifting, which can lead to further mechanical issues or driver frustration.

In contrast, while checks like the inertia brake calibration, gauge calibration, and fluid level checks are also important for vehicle operation and safety, they do not directly relate to the immediate functionality and effectiveness of the newly installed shifter assembly. Focusing on shifter calibration first ensures that the primary function of changing gears is optimized, setting a solid foundation for further adjustments or checks to be made later.