What can be checked using the setup in the mentioned figure?

The setup described in the question is typically utilized to assess the ring gear runout, which is crucial for determining the precision and alignment of the gear within the differential assembly. Runout refers to the amount of deviation from a true circle when the ring gear is rotated. Excessive runout can lead to increased wear, noise, and potential failure of the differential over time.

Using this setup, a technician can measure the amount of runout by rotating the ring gear and observing any variations that occur in its surface relative to a fixed reference point. If runout is greater than specified tolerances, adjustments or replacements may be necessary to ensure optimal performance and longevity of the drivetrain.

While the other options relate to different aspects of the differential setup, they do not apply directly to the specific measurement of runout, which is why the selected answer focuses solely on that aspect.