What action should be taken when setting preload on steering gear?

When setting the preload on steering gear, ensuring that the drag link is disconnected is the correct action because it allows for an accurate adjustment without interference from other components. Disconnecting the drag link removes any external pressures or forces that could affect the accuracy of the preload measurement and adjustment. This ensures that the steering gear can be properly adjusted to achieve the desired feel and responsiveness without the additional load from the connected steering system.

In contrast, adjusting with the truck loaded may induce variables that affect the steering gear's performance, while measuring preload while moving the wheels could lead to inaccurate readings due to dynamic forces at play. Setting preload at any steering angle may not provide consistent results, as the adjustment should be made under specific conditions to ensure optimal performance. Properly adjusting preload is crucial for effective steering response and overall vehicle handling, which underscores the importance of disconnecting the drag link during this procedure.