D Height Measurement

Fig 1: Measuring D Height Dimension

Courtesy of GENERAL MOTORS COMPANY

Measurement Definition 

D Height: The vertical distance from the midpoint of the lower control arm to knuckle mounting rear bolt head to midpoint of the lower control arm to rear subframe rear mounting bushing bolt head

Use the following procedure to check the D dimension:

NOTE:

The left and right D height difference should be no more than 10 mm (.39 in).

1. Push the rear bumper down a minimum of 25 mm (1 in). Perform this step three times.
2. Measure and record the trim height per the "Measurement Definitions" above.
3. Lift the rear bumper up a minimum of 25 mm (1 in), and release. Perform this step three times.
4. Measure and record the trim height per the "Measurement Definitions" above.
5. The true D height is the average of the measurements taken in steps 2 & 4. Refer to Trim Height Specifications 
6. If these measurements are out of specifications, inspect for the following conditions:
   • Worn or damaged suspension components
   • Collision damage