FixVault

D Height Measurement

NOTE: The D height dimension measurement determines the proper rear end ride height. There is no adjustment procedure. Repair may require replacement of suspension components.
  1. With the vehicle on a flat surface, lift upward on the rear bumper 1.5 in. (38 mm).
  2. Release vehicle.
  3. Allow the vehicle to settle into position.
  4. Repeat the jouncing operation 2 more times for a total of 3 times.
  5. The D height is obtained by measuring the distance between the edge of the jounce cup along the jounce bumper center line and the jounce pad on the rear axle. See Fig 1 .
  6. If these measurements are out of specifications, inspect for the following conditions:
    • Sagging front suspension. May need to replace torsion bar.
    • Sagging rear coil springs. May need to replace rear suspension Coil Springs.
    • Proper air suspension operation.
    • Worn rear suspension components.
    • Improper tire inflation.
    • Improper weight distribution.
    • Collision damage.
Fig 1: Measuring D Height
G00274028Courtesy of GENERAL MOTORS CORP.