Sierra 1500 2WD V6-4.3L (2008)
7. Install the runout gauge at the idler arm.
8. Push the tire inward slowly with one hand to remove any lash.
Zero out the runout gauge and pull outward in order to take a reading.
9. Allow only 1 mm (0.039 in) of movement at the idler arm ball stud.
If the movement is more than 1 mm (0.039 in) then replace the idler arm.