Frame & Underbody: Removal & Installation Chevrolet Silverado 3500

Removal Procedure

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Support the transmission with a transmission jack.
3. Remove the nut retaining the transmission mount to the transmission support.
4. Raise the rear of the transmission.
5. Remove the bolts and the nuts retaining the transmission support to the frame. (15 series)
6. Remove the bolts and the nuts retaining the transmission support to the frame. (25/35 series)
7. Remove the transmission support from the frame.

Installation Procedure

1. Install the transmission support to the frame. (15 series)
2. Install the transmission support to the frame. (25/35 series)
3. Install the bolts and the nuts in order to retain the transmission support to the frame. Tighten: Tighten the nuts to 95 N.m (70 lb ft).
4. Lower the rear of the transmission.
5. Install the transmission mount to the transmission support.
6. Install the nuts in order to retain the transmission mount to the transmission support. Tighten: Tighten the nuts to 40 N.m (30 lb ft).
7. Remove the transmission jack.
8. Lower the vehicle.

Scheme 4

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Remove the engine crossmember bolts.
3. Remove the engine crossmember.

1. Install the engine crossmember.
2. Install the engine crossmember bolts. Tighten: Tighten the engine crossmember bolts to 120 N.m (88 lb ft).
3. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Remove the differential carrier shield. Refer to «Shield Replacement»(ref-184180-S00879736072005082200000) in Front Drive Axle.
3. Remove the bolts retaining the crossmember to the frame.
4. Remove the crossmember from the vehicle.

1. Install the crossmember to the vehicle.
2. Install the bolts retaining the crossmember to the frame. Tighten: Tighten the crossmember retaining bolts to 120 N.m (88 lb ft).
3. Install the differential carrier shield. Refer to «Shield Replacement»(ref-184180-S00879736072005082200000) in Front Drive Axle.
4. Lower the vehicle.

Scheme 5

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Remove the bolts retaining the frame brace to the frame.
3. Remove the frame brace from the vehicle.

1. Install the frame brace to the vehicle.
2. Install the bolts retaining the frame brace to the frame. Tighten: Tighten the frame brace retaining bolts to 50 N.m (37 lb ft).
3. Lower the vehicle.

1. Remove the master cylinder. Perform the following steps: Remove the nuts retaining the master cylinder to the brake booster. Remove the master cylinder from the brake booster. Secure the cylinder away from the booster.
2. Raise the vehicle on the hoist. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
3. Remove the park brake equalizer intermediate cable. Perform the following steps: Remove the nut from the park brake equalizer intermediate cable. Remove the intermediate cable from the equalizer. Depress the retaining tabs that secure the park brake cable to the frame. Pull slightly on the cable from the mounting area in order to provide slack for body movement without binding the cable.
4. Remove the body mount bolts.
5. Properly support the body in the area that the mounts will be replaced.
6. Lower the chassis accordingly in order to remove the cushions (1) as necessary.

1. Install the cushions (1) as necessary and raise the chassis accordingly.
2. Install the body mount bolts. Tighten: Tighten the bolts to 85 N.m (63 lb ft).
3. Install the park brake equalizer intermediate cable. Perform the following steps: Pull rearward on the park brake cable to the original position. Secure the cable retaining tabs to the frame. Install the intermediate cable end to the equalizer. Install the nut to the threaded end of the intermediate cable. Tighten: Tighten the nut to 4 N.m (31 lb in).
4. Lower the vehicle.
5. Install the master cylinder. Perform the following steps: Mount the master cylinder to the brake booster. Install the master cylinder mounting nuts. Tighten: Tighten the nuts to 36 N.m (27 lb ft).

1. Remove the master cylinder. Perform the following steps: Remove the nuts retaining the master cylinder to the brake booster. Remove the master cylinder from the brake booster. Secure the cylinder away from the booster.
2. Raise the vehicle on the hoist. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
3. Remove the park brake equalizer intermediate cable. Perform the following steps: Remove the nut from the park brake equalizer intermediate cable. Remove the intermediate cable from the equalizer. Depress the retaining tabs that secure the park brake cable to the frame. Pull slightly on the cable from the mounting area in order to provide slack for body movement without binding the cable.
4. Remove the body mount bolts.
5. Properly support the body in the area that the mounts will be replaced.
6. Lower the chassis accordingly in order to remove the cushions (1) as necessary.

1. Install the cushions (1) as necessary and raise the chassis accordingly.
2. Install the body mount bolts. Tighten: Tighten the bolts to 85 N.m (63 lb ft).
3. Install the park brake equalizer intermediate cable. Perform the following steps: Pull rearward on the park brake cable to the original position. Secure the cable retaining tabs to the frame. Install the intermediate cable end to the equalizer. Install the nut to the threaded end of the intermediate cable. Tighten: Tighten the nut to 4 N.m (31 lb in).
4. Lower the vehicle.
5. Install the master cylinder. Perform the following steps: Mount the master cylinder to the brake booster. Install the master cylinder mounting nuts. Tighten: Tighten the nuts to 36 N.m (27 lb ft).

1. Disconnect the trailer wiring harness.
2. Remove the hitch platform bolts from the frame rails and the rear bumper.
3. Remove the hitch platform from the vehicle.

1. Position the hitch platform to the vehicle.
2. Install the platform hitch bolts to the frame rails and the rear bumper. Tighten: Tighten the bolts to 125 N.m (92 lb ft).
3. Connect the trailer wiring harness.

1. Remove the front bumper. Refer to «Bumper Replacement - Front (Old Style)»(ref-184170-S30294608362005082200000)
2. Remove the tow hook bolts from the frame rail.
3. Remove the tow hook from the vehicle.

1. Install the tow hook to the frame rail.
2. Install the bolts to the tow hook through the frame rail. Tighten: Tighten the bolts to 85 N.m (63 lb ft).
3. Install the front bumper. Refer to «Bumper Replacement - Front (Old Style)»(ref-184170-S30294608362005082200000) .

Scheme 6

1. Remove the tow hook bolts from the frame rail.
2. Remove the tow hook from the vehicle.

1. Install the tow hook to the frame rail.
2. Install the bolts to the tow hook through the frame rail. Tighten: Tighten the bolts to 85 N.m (63 lb ft).

1. Remove assist step pad bolts.
2. Remove assist step pad.

1. Install assist step pad.
2. Install assist step pad bolts. Torque bolts until fully seated but not stripped.

1. Remove the following components from the vehicle: The center body mount bolt (1) The lock washer The washer
2. Remove the center lower body-cushion assemblies (4).
3. Remove the following components from the assist step: The center bolt (2) The lock washer The washer
4. Remove the assist step center bracket (5).
5. With an assistant, remove the following front components, and rear components: The body mount bolts (1) The lock washers (2) The washers (3)
6. With an assistant, remove the assist step assembly from the vehicle.
7. Remove the lower body-mount cushion assemblies (4), front and rear, from the vehicle.
8. Remove the following components from the front assist step brackets, and from the rear assist step brackets: The bolts (1) The lock washers (2) The washers (3)
9. Remove the front brackets, and the rear brackets (4) from the assist step.
10. Remove the front gaskets, and the rear gaskets (5) from the assist step.

Scheme 7

Scheme 8

1. Install the front gaskets, and the rear gaskets (5) to the assist step.
2. Install the front brackets, and the rear brackets (4) to the assist step.
3. Install the following components to the front assist step bracket, and the rear assist step bracket: The washers (3) The lock washers (2) The bolts (1) Tighten: Torque the bolts to 90 N.m (66 lb ft).
4. Install the lower body-mount cushion assemblies (4), front and rear, to the vehicle.
5. With an assistant, raise the assist step to the vehicle.
6. With an assistant, install the following front components, and rear components: The washers (3) The lock washers (2) The body mount bolts (1) Tighten: Torque the bolts to 90 N.m (66 lb ft).
7. Install (5) the assist step center bracket.
8. Install (2) the following components to the assist step: The washer The lock washer The center bolt Tighten: Torque to 45 N.m (33 lb ft).
9. Install (1) the following components to the assist step: The washer The lock washer The center body mount bolt Tighten: Torque to 90 N.m (66 lb ft).

1. Remove the frame to the shield bolts.
2. Remove the shield from the vehicle. 15 Series is shown, 25 Series is similar.

1. Install the shield to the vehicle. 15 Series is shown, 25 Series is similar.
2. Install the shield to frame bolts. Tighten: Tighten the bolts to 20 N.m (15 lb ft).

1. Remove the battery ground (negative) cable.
2. Remove the frame bolt (2) from the frame crossmember nut.
3. Break away the spot welds (1) on one side of the frame crossmember nut retainer with an air chisel.
4. Lift one side of the frame crossmember nut retainer (enough to remove the frame crossmember nut).
5. Remove the frame crossmember nut.

1. Install the frame crossmember nut (2).
2. Install the lower frame crossmember nut retainer into place to insure proper placement and working condition of the frame crossmember nut.
3. Install the spot weld (3) frame crossmember nut retainer in the original location.
4. Clean and prepare the welded surfaces.
5. Install the new frame bolt to the frame crossmember nut. Tighten: Tighten the bolt to 180 N.m (133 lb ft).
6. With a pressure pot apply the anticorrosion compound GM P/N 12346225 or equivalent and coat the inside of the repair area through any access hole thoroughly.
7. Connect the battery ground (negative) cable.

Scheme 9

1. A datum is an imaginary horizontal plane that runs 2 ways to the vehicle: Below
2. Parallel Calculate the height dimensions at right angles from the datum to a given control reference point on the underbody.

The company that develops height dimensions determines the location of the datum based on the equipment used. Different datum lines are established for the same vehicle. Add or subtract an equal amount from all height dimensions. Create a new datum line for your usage.