The shear option in Surfer's transform dialog shears a map horizontally. If you would like the option to shear a map vertically in Surfer, please let us know.  In the meantime, the workflow below can be used to imitate a vertical shear of your map.

1. Rotate the grid file so that X and Y are switched:
1. Click Grids | Calculate | Transform.
2. In the Grid Transform dialog select your contour layer in the Input Grid field or click Browse to select the desired grid file. 
3. Change the Operation to Rotate and enter 270 (or the desired rotation angle) as the rotation angle
4. Enter a new Output Grid File name, if desired.
5. Uncheck Add grid as layer to and click OK.
6. Click OK in the Export Options dialog.
7. Click OK in the Surfer dialog indicating the new grid was created.
2. Click the Contours layer in the Contents window.
3. In the Properties window, click the open file icon in the Grid file field.
4. Select the rotated grid file created above and click Open.
5. If necessary, in the Surfer Warning, click Yes to adjust the map limits to include this layer.
6. Click Home |  Selection | Transform.
7. In the Transform dialog, enter the desired Shear value.
8. Enter 90 in the Rotation field and click OK.
9. If desired, you can now select the axes to rotate the labels and/or change which ones are displaying the ticks and labels.

Updated November 24, 2021