The basket shaft and arbor shaft configuration determines how grapes are placed on the sorting table depending on the direction of rotation. This means the grapes land on the upper side when driving along a slope and are automatically distributed on the sorting table. Rotation is automatically reversed when driving downhill. The grape harvester control system automatically detects upward gradients and adjusts speeds and rotational direction when the harvester moves uphill or downhill along a gradient of 15% longer than two seconds.