GM Service Manual Online
For 1990-2009 cars only

Notice: The cab must be properly supported and the weight of the cab evenly distributed during cab mount replacement. Failure to provide proper support could result in damage to the vehicle.

Ensure to support the cab properly while changing the mount. Tilt the hood and install lifting straps. Refer to Cab Replacement . If changing only one mount, remove the nut on the bottom of the other mount and the nuts beneath the rear support. Removing these nuts will allow the cab to be lifted enough to provide clearance. If lifting straps cannot be used, place jacks under the cab. Position one jack near the mount being replaced. Place another jack under one of the longitudinal sills running from the front to the rear of the cab under the floor. Place a strong block of wood at least 150 mm x 150 mm (6 in x 6 in) between the jack and the cab sill in order to distribute the weight of the cab.

Removal Procedure


    Object Number: 818850  Size: SH
  1. From underneath the cab, remove the nut and the washer from both of the front mounts.
  2. Remove the nut and the washer from beneath the rear support.
  3. Remove the 2 nuts and the washers.
  4. Remove the front floor mat.
  5. Remove the inner rocker panel plug from the floor at the mount to be replaced.
  6. Remove the front cab mounting bolt from the floor.
  7. Raise the cab enough to permit removal of the 2 cab mount to frame bracket bolts.


    Object Number: 816311  Size: SH
  8. Remove the 2 bolts and nuts that secure the cab mount assembly to the frame rail bracket.
  9. Remove the mount assembly and the retainers from the frame rail bracket on the frame rail.

Installation Procedure


    Object Number: 816311  Size: SH
  1. Install the cab mount assembly and the retainers between the cab and the frame bracket.
  2. Install the 2 short bolts, the washers, the spacers, and the nuts through the cab mount and the mounting bracket.
  3. Install the cab mounting bolt through the plate, the floor, the mount assembly, and the frame bracket.

  4. Object Number: 818850  Size: SH
  5. Install the mounting bolt washer and nut to the bottom of the cab mounting bolt.
  6. Notice: Refer to Fastener Notice in the Preface section.

  7. Lower the cab.
  8. Tighten

        • Tighten the cab mount to cab bolts/nuts to 185 N·m (136 lb ft).
        • Tighten the cab mount assembly to frame bracket bolts to 100 N·m (74 lb ft).
  9. Install the inner rocker panel plug to the floor.
  10. Install the floor mat.