GMC Yukon Owner's Manual page 522

2. Remove the wing nut (B) used to retain the tool
bag by turning it counterclockwise.
3. Turn the knob (A) on the jack counterclockwise
to release the jack and wheel blocks from the
bracket.
4. Remove the wheel blocks and the wheel
block retainer by turning the wing nut (C)
counterclockwise.
6-90
The tools you will be using include the following:
A. Jack D. Jack Handle Extensions
B. Wheel Blocks E. Wheel Wrench
C. Jack Handle