Frame and Underbody Cadillac Escalade GMT800

Fastener Tightening Specifications

FASTENER TIGHTENING SPECIFICATIONS

Scheme 1

DIMENSIONS - FRAME (1500 SUBURBAN/YUKON XL 2WD/4WD)

Dimensions - Frame (1500 Suburban/Yukon XL/Avalanche 2WD & 4WD)

Point-to-point measurements are for reference only. Use these measurements for diagnosis or for validating. Point-to-point measurements do not afford the accuracy that 3-Dimensional measuring systems have. Point-to-point measurements are duplicated with tram bar pointers set at equal lengths. All holes, slots and fasteners are measured to the center.

Scheme 2

DIMENSIONS - FRAME (1500 SUBURBAN/YUKON XL/AVALANCHE 2WD & 4WD)

Dimensions - Frame (1500 Tahoe/Yukon/Escalade 2WD/4WD)

Point-to-point measurements are for reference only. Use these measurements for diagnosis or for validating. Point-to-point measurements do not afford the accuracy that 3-Dimensional measuring systems have. Point-to-point measurements are duplicated with tram bar pointers set at equal lengths. All holes, slots and fasteners are measured to the center.

Scheme 3

DIMENSIONS - FRAME (1500 TAHOE/YUKON/ESCALADE 2WD/4WD)

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DIMENSIONS - FRAME (1500 YUKON/TAHOE/ESCALADE 2WD/4WD)

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DIMENSIONS - FRAME (2500 SUBURBAN/YUKON XL/AVALANCHE 2WD)

Dimensions - Frame (2500 Suburban/Yukon XL/Avalanche 2WD)

Point-to-point measurements are for reference only. Use these measurements for diagnosis or for validating. Point-to-point measurements do not afford the accuracy that 3-Dimensional measuring systems have. Point-to-point measurements are duplicated with tram bar pointers set at equal lengths. All holes, slots and fasteners are measured to the center.

Scheme 6

DIMENSIONS - FRAME (2500 SUBURBAN/YUKON XL/AVALANCHE 2WD)

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DIMENSIONS - FRAME (2500 SUBURBAN/YUKON XL/AVALANCHE 4WD)

Dimensions - Frame (2500 Suburban/Yukon XL/Avalanche 4WD)

Point-to-point measurements are for reference only. Use these measurements for diagnosis or for validating. Point-to-point measurements do not afford the accuracy that 3-Dimensional measuring systems have. Point-to-point measurements are duplicated with tram bar pointers set at equal lengths. All holes, slots and fasteners are measured to the center.

Scheme 8

DIMENSIONS - FRAME (2500 SUBURBAN/YUKON XL/AVALANCHE 4WD)

Checking Frame Alignment

The main components of the frame are the side rails and the crossmembers. The rails carry the load. The crossmembers stabilize the rails.

The 5 types of frame misalignment are the following

1. Sag
2. Buckle
3. Diamond
4. Sidesway
5. Twist

A misaligned frame rail may move in the following directions from where the frame rail should be

1. Forward
2. Up
3. Down
4. To the side

The easiest way to inspect the frame alignment is with gauges that are made for this purpose. Detailed instructions are normally supplied with the gauges at the time of purchase. There are no instructions for gauge use in the manual.

Whether you inspect the alignment with or without gauges, park the vehicle on a level section of floor.

Certain conditions call for preliminary inspections before inspecting the frame. Suspension or axle problems may make it appear that the vehicle frame is out of alignment. If an axle has shifted, diamond or sidesway may appear to exist when neither does exist. A weak spring may make the vehicle appear to have a twisted frame.

A visual inspection of the top and the bottom flanges of each rail may reveal the specific area where the sag or the buckle exist.

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1. Raise the vehicle. Refer to «JACKING AND LIFTING - AVALANCHE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche) 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.

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1. Install the transmission support to the frame. (15 series)
2. Install the transmission support to the frame. (25/35 series) NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
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.

Removal Procedure

Support the frame with the hoist when you change the body mounts. If only one mount is changed loosen and lower the entire side on which the mount in question is being replaced.

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1. Raise the vehicle on a hoist. Refer to «JACKING AND LIFTING - AVALANCHE»(/cadillac/escalade/gmt800-2001-2006/remont/hoistjack/#jacking-and-lifting-avalanche) in General Information.
2. Using jack stands or the equivalent to support the body where the mounts will be replaced.
3. Remove the body mount bolt, retainer, and lower cushion at the radiator support.
4. Remove the body mount bolt, retainers, and lower cushions at the front mount location.
5. Remove the body mount bolt, retainers, and lower cushions at the other mount locations.
6. Remove the body mount bolt, retainers, and lower cushion at the rear most mount.
7. Disconnect or remove any wiring harness or component that may interfere with the lowering of the frame.
8. Lower the hoist in order to leave the body supported by the jack stands.
9. Remove the upper cushions and the shims from the vehicle.

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1. Install the upper cushions and the shims to the vehicle.
2. Raise the hoist to allow the body mount bolts to be installed.
3. Connect or install any wiring harness or component that was removed to allow for the lowering of the frame. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
4. Install the body mount bolt, retainer, and lower cushion at the rear most mount.
5. Install the body mount bolt, retainers, and lower cushions at the other mount locations.
6. Remove the body mount bolt, retainers, and lower cushions at the front mount location.
7. Install the body mount bolt, retainer, and lower cushion at the radiator support. Tighten Tighten the bolts to 85 N.m (63 lb ft).
8. Remove the jack stands.
9. Lower the vehicle.

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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.

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1. Position the hitch platform to the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
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.

Scheme 27

1. Remove the front bumper. Refer to «BUMPER REPLACEMENT - FRONT (OLD STYLE)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-body-panels/#bumper-system)
2. Remove the tow hook bolts from the frame rail.
3. Remove the tow hook from the vehicle.

Scheme 28

1. Install the tow hook to the frame rail. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
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)»(/cadillac/escalade/gmt800-2001-2006/remont/exterior-body-panels/#bumper-system) .

Scheme 29

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

Scheme 30

1. Install the tow hook to the frame rail. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
2. Install the bolts to the tow hook through the frame rail. Tighten Tighten the bolts to 85 N.m (63 lb ft).

Assist Step Replacement (Denali/Escalade)

Removal Procedure

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1. Remove the push-in retainer from the assist step front cover.
2. Remove the cover from the vehicle.
3. Remove the retainer clip from the assist step rear cover.
4. Remover the cover from the vehicle.
5. Remove the bottom fender bolt (2) and the washer (1) from the vehicle.
6. With the aid of an assistant, remove the bolts (1, 5) and the nuts (2, 3) from the assist step brackets.
7. Remove the assist step from the vehicle.
8. Remove the heater and A/C tubes retaining nuts from the studs, if equipped. Refer to «HEATER PIPE REPLACEMENT -- AUXILIARY»(/cadillac/escalade/gmt800-2001-2006/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
9. Remove the assist step bolts (6) from the brackets.
10. Remove the brackets (4) from the vehicle.

Installation Procedure

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1. Install the assist step brackets to the vehicle (4).
2. Install the bolts (6) to the brackets and ensure that the brackets are seated securely to the inner rocker panel.
3. Install the heater and A/C tubes retaining nuts to the studs, if equipped. Refer to «HEATER PIPE REPLACEMENT -- AUXILIARY»(/cadillac/escalade/gmt800-2001-2006/remont/manual-hvac-system/#heating-ventilation-and-air-conditioning) in Heating, Ventilation, and Air Conditioning.
4. With the aid of an assistant, install the assist step to the vehicle.
5. Install the bolts (1, 5) and the nuts (2, 3) to the assist step bracket, and leave the nuts loose. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
6. Install the bottom fender bolt (2) and the washer (1) to the vehicle. Tighten Tighten the bottom fender bolt (2) to 25 N.m (18 1b ft).
7. Tighten the assist step fasteners in the following sequence: Tighten 7.1. Tighten the bracket bolt (6) to 25 N.m (18 1b ft). 7.2. Tighten the assist step bracket nut (2) to 9 N.m (80 lb in). 7.3. Tighten the assist step to the bracket nut (3) to 9 N.m (80 lb in).
8. Install the assist step rear cover to the vehicle.
9. Install the clip retainer.
10. Install the assist step front cover to the vehicle.
11. Install the push-in retainer.

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1. With the aid of a helper, remove the retaining nuts and the spacers (1) from the bottom side of the assist step, and remove the assist step from the vehicle.
2. Remove the rocker panel molding. Refer to «MOLDING REPLACEMENT - ROCKER PANEL (Z-71)»(/cadillac/escalade/gmt800-2001-2006/remont/exteriorinterior-trim/#exterior-trim) or «MOLDING REPLACEMENT - ROCKER PANEL (UTILITY)»(/cadillac/escalade/gmt800-2001-2006/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
3. Drill out the rivets (1) from the assist step brackets.
4. Remove the 5 stud plates (1) from the 5 assist step brackets (2).
5. Remove the 5 retaining bolts (1) from the inner side of the rocker panel.
6. Remove the 5 retaining bolts (2) from the inner side of the rocker panel.
7. Remove the assist step brackets (5) from the vehicle.
8. Drill out the rivets (3) for the rocker panel molding bracket (4).
9. Remove the bracket (4) from the vehicle.

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1. Install the rocker panel molding bracket (4) to the vehicle.
2. Install the rivets (3) that secure the rocker panel molding bracket (4) to the vehicle.
3. Install the assist step brackets (5) to the vehicle. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
4. Install the 5 retaining bolts (1) to the inner side of the rocker panel. Tighten Tighten the bolts (1) to 29 N.m (21 lb ft).
5. Install the 5 retaining bolts (2) to the inner side of the rocker panel. Tighten Tighten the bolts (1) to 10 N.m (89 lb in).
6. Install the 5 stud plates (1) to the 5 assist step brackets (2).
7. Install the rivets (1) that secure the assist step brackets to the rocker panel.
8. Install the rocker panel molding. Refer to «MOLDING REPLACEMENT - ROCKER PANEL (Z-71)»(/cadillac/escalade/gmt800-2001-2006/remont/exteriorinterior-trim/#exterior-trim) or «MOLDING REPLACEMENT - ROCKER PANEL (UTILITY)»(/cadillac/escalade/gmt800-2001-2006/remont/exteriorinterior-trim/#exterior-trim) in Exterior Trim.
9. With the aid of an assistant, install the assist step to the vehicle.
10. Install the spacers and the nuts (1). Tighten Tighten the bolts (1) to 29 N.m (21 lb ft).

Scheme 48

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

Scheme 49

1. Install the shield to the vehicle. 15 Series is shown, 25 Series is similar. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
2. Install the shield to frame bolts. Tighten Tighten the bolts to 20 N.m (15 lb ft).

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1. Remove the battery ground (negative) cable.
2. Remove the frame bolt (2) from the frame crossmember nut. IMPORTANT: The frame crossmember nut retainer will be reused if not damaged from the stripped out bolt.
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.

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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. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in GM VEHICLES CAUTIONS & NOTICES .
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.

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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.

Scheme 55

A centerline is an imaginary vertical plane that is perpendicular to the length of the datum plane through the center of the vehicle. The centerline is any line drawn through the center of the vehicle's datum. The symbol for centerline is CL.

Length

Centerline length measurements are 3 dimensional measurements. The 3 dimensions are the following

1. Length, the distance between 2 points when the height is parallel to the center plane.
2. Height, the measurement is parallel to the datum plane.
3. Width, the measurement is parallel to the center plane.

Show the horizontal width and length dimensions of the underbody from the bottom of the underbody. Show the vertical dimensions from the side of the underbody. Use the datum plane as a base for all vertical, height, measurements.

Scheme 56

The vertical body 0 line is a line drawn through the frame either at the forward or rearward torque box area of the frame.

Frame Reference Point Description

Reference points are locations on a vehicle which correspond to specific measuring points. Use the reference points when checking the vehicle structure.

Dimension charts may use the center of a hole, bolt head, or nut, etc. as a reference point. A description and location chart will tell you how and where the measurements should be taken. The most accurate reference point is a gauge hole or a control hole used by the assembly plant in order to control tolerances when the vehicle was built. Refer to FRAME CONTROL HOLE DESCRIPTION on for more information about control holes.

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Control holes are round or oval holes located in the underbody structure sections, the upper body, and the body sides. Some control holes can be identified from other holes by a turned up lip on the inside of the hole. This reinforced lip reduces the possibility of hole distortion and increases accuracy during assembly. Utilize control points whenever possible when measuring underbody dimensions, in order to obtain the most accurate readings.

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Symmetrical reference points are 2 corresponding points on opposite sides of the centerline that have equal specifications in length, width, and height. Use symmetrical reference points in order to make quick inspections for underbody structural damage.

Frame Reference Point Description - Asymmetrical

When 2 corresponding reference points have different measurements, they are called asymmetrical. If you perform a quick cross check and the measurements are unequal, you should check the dimension charts in order to find out if the measuring points are symmetrical or asymmetrical.

Minimizing Frame Service Description

Frame service can be minimized by lessening the concentration of stress in small areas of the frame.

1. Use vehicles only for the purposes for which they were designed. Do not overload the vehicle. Load the vehicle evenly. Avoid localized loads. Do not operate the vehicle on extremely rough terrain at excessive speeds. Determine the forces placed on a frame from the operation of equipment when picking a frame for a new vehicle or reinforcing a frame.
2. Follow the recommended practices when repairing a frame. Follow the recommended practices when mounting a body or equipment on a frame. Avoid sudden changes in the section modulus. Do not drill holes in the frame rail flanges. Space holes in the web section of a rail at least 13 mm (1/2 inch) apart. Use existing holes whenever possible. Do not cut holes with a torch. Do not overheat the frame rails. Avoid welding on the flanges. Do not allow 4 or more holes to exist on the same vertical line of the web.

See also:
• JACKING AND LIFTING - AVALANCHE
• FASTENER NOTICE
• BUMPER REPLACEMENT - FRONT (OLD STYLE)
• HEATER PIPE REPLACEMENT -- AUXILIARY
• MOLDING REPLACEMENT - ROCKER PANEL (Z-71)
• FRAME CONTROL HOLE DESCRIPTION