Arrow points to the section to be replaced.

When a collision involves damage to a vehicle’s frame, a sectioning procedure may sometimes be required to help restore the vehicle to its pre-accident condition.

Sectioning is the process of cutting a portion of a vehicle part — such as a frame — then removing and replacing it with a new service part (many of which are available through GM Genuine Parts).

When sectioning a part on GM vehicles, it’s critical to follow GM-approved repair procedures in Service Information (SI) while heeding the various notes and warnings that appear.


The following is an example of some of the key steps involved in a front full-frame sectioning procedure on GM’s new T1 SUVs — the 2021 Tahoe, Suburban, Yukon and Escalade.


1. Disable the SIR (Supplemental Inflatable Restraint) system.

2. Disconnect the battery’s negative cable.

3. Remove all related panels and components.

4. Remove the frame rail reinforcement.

5. Remove the sealers and anti-corrosion materials from the repair area as necessary.

6. Using a grinding wheel or equivalent, remove the weld (1) from the front section of the frame rail.
Note: Do not damage or cut attaching panels and reinforcements.

7. Remove the frame rail from the vehicle.



1. Prepare the service frame rail per installation requirements.

2. Prepare all joining surfaces for welding as necessary.

3. Apply weld-thru coating or equivalent to all welding surfaces.

4. Position the frame rail (A) with the vehicle using 3-dimensional measuring equipment, and then clamp into place.


5. Verify the frame measurements 3-dimensionally to ensure proper position of the service frame.

6. Continuous-weld the upper and outer joints through each corner.

7. Continuous-weld the inner and lower joints (B in image below) through each corner.


8. Install the frame rail reinforcement.

9. Apply any sealers and anti-corrosion materials to the repair area as necessary. Note: Before refinishing, refer to the Anti-Corrosion Treatment and Repair section in SI.

10. Paint the repaired area.

11. Install all related panels and components.

12. Connect the battery’s negative cable.

13. Enable the SIR system.

For additional frame sectioning details, refer to Doc #5343390 in Service Information.