D Height Measurement

Courtesy of GENERAL MOTORS COMPANY

Measurement Definitions 

The D Height: The vertical distance from the center of the bolt head attaching the lower control arm to the knuckle (1) to the center of the bolt head attaching the lower control arm to the cradle (2).

Use the following procedure to check the D dimension:

NOTE:

The left and right D height difference should be no more than 10 mm (0.39 in).

1. Push the rear bumper down a minimum of 25 mm (1 in) and release. 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 and 4. Trim Height Specifications 
6. If these measurements are out of specifications, inspect for the following conditions:
   • Worn or damaged suspension components
   • Collision damage