D Height Measurement

Fig 1: Checking D Dimension

Courtesy of GENERAL MOTORS CORP.

The D height dimension measurement determines the proper rear end ride height. There is no adjustment procedure. Repair may require replacement of suspension components.

Use the following procedure to check the D dimension:

1. With the vehicle on a flat level surface, lift upward on the rear bumper 38 mm (1.59 in).
2. Gently remove your hands and allow the vehicle to settle.
3. Repeat the jouncing operation 2 more times.
4. Measure the D height for the left and right side of the vehicle. Measure the vertical distance of the lower control arm inner bolt.
5. Measure the vertical distance between the lower control arm outer bolt.
6. Obtain the difference between the 2 measurements for the actual D height measurement.
7. Repeat this task for the other side of the vehicle.
8. Using your hands, jounce the front of the vehicle downward approximately 38 mm (1.59 in).
9. Gently remove your hands and allow the vehicle to settle.
10. Repeat the jouncing operation 2 more times.
11. Measure the D height dimension.
12. The true D height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications .
13. If these measurements are out of specifications, inspect for the following conditions:
    • Worn or damaged suspension components
    • Collision damage