GM Service Manual Online
For 1990-2009 cars only

All dimensions are from the center of any bolt or hole. Measurements must be correct within 1.6 mm (1/16 in) of the dimensions given in order for the structure to be considered aligned.

Quick Method


Object Number: 3318  Size: SH

Use the control holes in order to quickly determine if underbody structural damage exists:


Object Number: 316435  Size: SH
  1. Diagonal measurements from point 5 to point 3 and from point 6 to point 4 should be equal.
  2. Measurements from point 6 to point 2 and from point 3 to point 1 should be equal.
  3. Measurements from point 5 to point 2 and from point 4 to point 1 should be equal.

Standard Method

Horizontal Frame Dimensions (RWD)


Object Number: 316168  Size: SH

Horizontal Frame Dimensions (4WD)


Object Number: 316207  Size: SH

Verify that the horizontal dimensions are correct.

Vertical Frame Dimensions (RWD)


Object Number: 316209  Size: SH
(1)Datum Line

Vertical Frame Dimensions (4WD)


Object Number: 316210  Size: SH
(1)Datum Line

Verify that the vertical dimensions are correct.