General Information: Other GMC Cab & Chassis Sierra 3500 HD

US English/Metric Conversion

Decimal and Metric Equivalents

Arrows and Symbols

This service manual uses various symbols in order to describe different service operations.

Scheme 9

Customer Concern Verification Sheets

The GM Customer Concern Verification Sheets have been designed to improve communications between the service customer and the technician. The more clearly the technician understands the concern and its symptoms, the more likely the concern will be fixed right the first time.

The GM-wide Customer Concern Verification Sheets are available in DealerWorld. The Customer Concern Verification Sheets may be printed and reproduced locally.

Dealers

All U.S. Dealers participating in the Common Training Program can enroll through the Common Training System Website at https://www.gmtraining.com. Within the website, there are individual training paths that are designed to assist in planning the training needs for each individual. Technicians should advise their Service Manager of their training needs including course names and course numbers. Dealers who have questions about Common Training should contact the Common Training help desk at 1-888-748-2687. The help desk is available Monday through Friday, 8:00 am-8:00pm Eastern Standard Time, excluding holidays. For GM Access support, contact the GM Access Help Desk at 1-888-337-1010.

Fleets

GM Fleet customers with GM Warranty In-Shop agreements are able to participate in service technical training through Common Training/GM Service Technical College (STC).

Assistance for all GM fleet customers using GM STC products and services is provided on the Internet via www.gmtraining.com using the "Contact Us" button on the site and/or the Common Training Help Desk at 1-888-748-2687. To order GM STC Training Materials, please contact the GM Training Materials Headquarters at 1-800-393-4831.

Most GM STC course materials have associated charges.

To purchase authentic GM STC Training Materials, contact the GM Training Materials Headquarters at 1-800-393-4831.

Non-GM Dealer Technicians

Technicians training for non-GM dealers is available through ACDelco. This training is for ACDelco customers employed in the automotive or truck service industry.

ACDelco courses are available at all approved GM Training Centers. Availability and schedules can be obtained by calling 1-800-825-5886 or contact us via the web at www.acdelcotechconnect.com and select the training button. Clinics are also offered through ACDelco Warehouse Distributors. Contract your dealer directly for more information.

Scheme 10

The vehicle identification number (VIN) plate is the legal identifier of the vehicle. The VIN plate is located on the upper left corner of the instrument panel. The VIN number can be seen through the windshield from the outside of the vehicle

Vehicle Identification Number (VIN) System

RPO Code List (Light Duty)

RPO Code List (Heavy Duty)

Metric Fasteners

This vehicle provides fastener dimensions using the metric system. Most metric fasteners are approximate in diameter to equivalent English fasteners. Make replacements using fasteners of the same nominal diameter, thread pitch, and strength.

A number marking identifies the OE metric fasteners except cross-recess head screws. The number also indicates the strength of the fastener material. A Posidrive® or Type 1A cross-recess identifies a metric cross-recess screw. For best results, use a Type 1A cross-recess screwdriver, or equivalent, in Posidrive® recess head screws.

GM Engineering Standards and North American Industries have adopted a portion of the ISO-defined standard metric fastener sizes. The purpose was to reduce the number of fastener sizes used while retaining the best thread qualities in each thread size. For example, the metric M6.0 X 1 screw, with nearly the same diameter and 25.4 threads per inch replaced the English 1/4-20 and 1/4-28 screws. The thread pitch is midway between the English coarse and fine thread pitches.

Scheme 11

The most commonly used metric fastener strength property classes are 9.8 and 10.9. The class identification is embossed on the head of each bolt. The English, inch strength classes range from grade 2 to grade 8. Radial lines are embossed on the head of each bolt in order to identify the strength class. The number of lines on the head of the bolt is 2 lines less than the actual grade. For example, a grade 8 bolt will have 6 radial lines on the bolt head. Some metric nuts are marked with a single digit strength identification number on the nut face.

The correct fasteners are available through GM SPO. Many metric fasteners available in the aftermarket parts channels are designed to metric standards of countries other than the United States, and may exhibit the following

1. Lower strength
2. No numbered head marking system
3. Wrong thread pitch

The metric fasteners on GM products are designed to new, international standards. The following are the common sizes and pitches, except for special applications

1. M6.0 X 1
2. M8 X 1.25
3. M10 X 1.5
4. M12 X 1.75
5. M14 X 2.00
6. M16 X 2.00

Adhesive Coated Fasteners

These fasteners accomplish the thread interface by the presence of a thread-locking compound on the fastener threads. Refer to the appropriate repair procedure in order to determine if the fastener may be reused and the applicable thread-locking compound to apply to the fastener.

Scheme 12

A prevailing torque fastener may be reused ONLY if

1. The fastener and the fastener counterpart are clean and not damaged
2. There is no rust on the fastener
3. The fastener develops the specified minimum torque against its counterpart prior to the fastener seating

Metric Prevailing Torque Fastener Minimum Torque Development

English Prevailing Torque Fastener Minimum Torque Development

Thread Inserts

General Purpose Thread Repair Kits.

These kits are available commercially.

Repair Procedure

1. Determine the size, the pitch, and the depth of the damaged thread. If necessary, adjust the stop collars on the cutting tool and tap to the required depth.
2. Drill out the damaged threads. Clean out any chips.
3. Lubricate the tap with light engine oil. Tap the hole. Clean the threads.
4. Thread the thread insert onto the mandrel of the installer. Engage the tang of the insert onto the end of the mandrel.
5. Lubricate the insert with light engine oil, except when installing in aluminum and install the insert.
6. If the tang of the insert does not break off when backing out the installer, break the tang off with a drift.

Registered and Non-Registered Trademarks

Listed below are Registered Trademarks (®) or Non-Registered Trademarks (™) which may appear in this service manual.

Scheme 13

The internal lock cylinder only uses 4 of the ten cut positions, 7 through 10. The tumbler positions are on one side and self-retaining.

1. Rotate the cylinder (1) so the side with tumbler spring wells faces up.
2. Insert the tumbler springs (2) into the 4 spring wells.
3. Install the first tumbler (3) for key cut position 7 in the slot nearest to the front of the lock cylinder. Install the remaining tumblers following the key code.
4. Press the tumblers in place until they are secure.
5. Check for correct loading of the tumblers by inserting the key into the cylinder. All tumblers should be flush with the lock cylinder body.

Scheme 14

The door lock cylinder only uses 7 of the 10 cut positions, 3 through 9. The tumbler positions are staggered from side to side, 4 on one side and 3 on the other side, are self-retaining. The left and right door lock cylinders are identical. The lever assembly determines which side of the vehicle the lock cylinder is for. After removing the current lock, record which lever is used and the orientation of rod clip.

1. Rotate the cylinder (1) so the side with the 4 tumbler spring wells faces up.
2. Insert the tumbler springs (2) into the 4 spring wells.
3. Install the tumbler (3) for key cut position 3 in the slot closest to the cylinder. Install the remaining tumblers, key cut positions 5, 7 and 9, following the key code and same process. Press the tumblers in place until they are secure.
4. Check the correct loading of the tumblers by inserting the key into the cylinder. All tumblers should be flush with the lock cylinder body.
5. Turn the cylinder so the side with the 3 tumbler spring wells faces up.
6. Insert the tumbler springs into the 3 spring wells.
7. The first tumbler closest to the front of the lock cylinder to be loaded will be the fourth key cut position. Install the remaining tumblers for key cut positions 6 and 8. Press the tumblers in place until they are secure.
8. Check the correct loading of the tumblers by inserting the key into the cylinder. All of the tumblers should be flush with the lock cylinder body.
9. Apply lubricant to the cylinder body and tumbler surfaces along with a small amount in the head of the cylinder using the supplied grease.
10. Install 2 springs (4) into the spring wells in the head of the lock cylinder.
11. Snap the shutter assembly (5) into the cylinder.
12. Assemble the cylinder into the case (6).
13. Align dimples of the cylinder cap (7) with the 4 recesses in the cap. Secure by pressing the cap into place with light hand pressure.
14. If required, assemble the rod clip (9) to the lever (8) using the recorded lever information.
15. Assemble the lever to the lock. Use E-clip (10) to retain the lever assembly.
16. If supplied, assemble the gasket to the lock.
17. Insert the key into the lock and function the lock to check for proper assembly and smooth operation.

Scheme 15

The ignition lock cylinder only uses 7 of the 10 cut positions, 2 through 8. The ignition cylinder tumblers (3) are located on alternate sides of the cylinder (1). They are snap-in and self-retaining. It follows the key code with the first tumbler being the first depth of the key code, closest to the head of the key.

1. Hold the ignition cylinder assembly (1) so that the side with the tumbler spring pocket located closest to the head of the cylinder is facing up.
2. Insert the tumbler springs (2) into each of the 4 spring pockets of the cylinder assembly.
3. The first tumbler (3) to be loaded will be the second key cut position, the second number in the key code. Install the first tumbler in the slot over the spring. Install the remaining tumblers for cuts 2, 4, 6, and 8 following the key code and the same process. Press the tumblers in place until they are secure.
4. Rotate the cylinder assembly. Insert the tumbler spring (2) into each of the spring pockets of the cylinder assembly (1).
5. The first tumbler (3) to be loaded will be the third key cut position, the third number in the key code. Install the first tumbler in the slot over the spring. Install the remaining tumblers for cuts 5, 7, and 9 following the key code and the same process. Press the tumblers in place until they are secure.
6. Inspect for correct loading of the tumblers by inserting the key into the cylinder. The side bar should drop flush with the lock cylinder body diameter.
7. Lightly lubricate the outside surfaces in the tumbler area of the lock body and down the key slot using the provided grease. Insert and extract the key 5 times to lubricate the keyway.
8. Line up the lock to the run position. Insert the lock in the steering column. Rotate the lock to key out position and remove the key. Insert the key and rotate the lock 3 times to distribute the grease from the lock to the column housing inside diameter.

Rear Compartment Lid and Liftgate Lock Cylinder Coding

The deck lock cylinder only uses 7 of the 10 cut positions, 4 through 10. The tumbler positions are staggered from side to side, 4 on one side and 3 on the other side. The deck lock cylinder tumblers are self-retaining. After removing the current lock, identify the direction the lever or switch is attached to tail of the lock.

1. Rotate the cylinder (1) so the side with the 4 tumbler spring wells faces up.
2. Insert the tumbler springs (2) into the 4 spring wells.
3. Install the tumbler (3) for key cut position 4 in the slot closest to the cylinder. Install the remaining tumblers, key cut positions 6, 8 and 10, following the key code and same process. Press the tumblers in place until they are secure.
4. Check the correct loading of the tumblers by inserting the key into the cylinder. All tumblers should be flush with the lock cylinder body.
5. Turn the cylinder so the side with the 3 tumbler spring wells faces up.
6. Insert the tumbler springs into the 3 spring wells.
7. The first tumbler closest to the front of the lock cylinder to be loaded will be the fifth key cut position. Install the remaining tumblers for key cut positions 7 and 9. Press the tumblers in place until they are secure.
8. Check the correct loading of the tumblers by inserting the key into the cylinder. All of the tumblers should be flush with the lock cylinder body.
9. Apply lubricant to the cylinder body and tumbler surfaces along with a small amount in the head of the cylinder using the supplied grease.
10. Install 2 springs (4) into the spring wells in the head of the lock cylinder.
11. Snap the shutter assembly (5) into the cylinder.
12. Assemble the cylinder into the case (6).
13. Align dimples of the cylinder cap (7) with the 4 recesses in the cap. Secure by pressing the cap into place with light hand pressure. If the package contains a switch assembly instead of a lever, assembly switch to back of the lock matching the orientation of the lock removed. Place washer on top of switch and secure with retainer clip (10).
14. If required, assemble the rod clip (9) to the lever (8) using the recorded lever information.
15. Assemble the lever to the lock. Use retainer clip (10) to retain the lever assembly.
16. If supplied, assemble the gasket to the lock.
17. Insert the key into the lock and function the lock to check for proper assembly and smooth operation.

Scheme 16

The internal lock cylinder only uses 5 of the 10 cut positions, 6 through 10. The tumbler positions are on one side and self-retaining.

1. Rotate the cylinder (1) so the side with the 5 tumbler spring wells faces up.
2. Insert the tumbler springs (2) into the 4 spring wells.
3. Install the tumbler (3) for key cut position 6 in the slot closest to the cylinder head. Install the remaining tumblers, key cut positions 8 and 10, following the key code and the same process. Press the tumblers in place until they are secure.
4. Check for correct loading of the tumblers by inserting the key into the cylinder. All of the tumblers should be flush with the lock cylinder body.
5. Turn the cylinder so the side with the 3 tumbler spring wells faces up.
6. Insert tumbler springs into the 2 spring wells.
7. The first tumbler closest to the front of the lock cylinder to be loaded will be the seventh key cut position. Install the remaining tumblers for key cut position 9, following the key code and same process. Press the tumblers in place until they are secure.
8. Check for correct loading of the tumblers by inserting the key into the cylinder. All of the tumblers should be flush with the lock cylinder body.
9. Apply lubricant to the cylinder body and tumbler surfaces along with a small amount in the head of the cylinder using the supplied grease.
10. Install 2 springs (4) into the 2 spring wells in the head of the cylinder.
11. Snap the shutter assembly (5) into the cylinder.
12. Insert the retainer spring (10) in the retainer pocket making sure it is positioned on the spring post.
13. Place the retainer bolt (11) in the pocket with the angle facing the back of the case. Depress the retainer bolt and hold.
14. With the key still in the cylinder, insert into case (6) 90 degrees to the right of the drain slot/retainer.
15. Rotate back 90 degrees to the key out position. Hold lock in case and remove the key. The cylinder should secure bolt in case.
16. Place the lock cylinder cap (7) on top of the lock assembly. Bend tabs on cap to underside of case making sure they are secure and pulled tight to case.
17. Insert key and rotate to verify the lock was assembled properly. The key should not be able to be removed when bolt is down. The lock should only rotate clockwise 90 degrees.
18. Assembly gaskets (9), if supplied in the groove located at the end of the case and gasket (8) in the grove at the front of the case.

Lifting and Jacking the Vehicle

For lifting the vehicle, various lift points are recommended. Before you begin any lifting procedure, place the vehicle on a clean, hard, level surface. Verify that all the lifting equipment meets weight standards and is in good working order. Verify that all of the vehicle loads are equally distributed and secure. If you are only supporting the vehicle at the frame side rails, verify that the lifting equipment does not put too much stress on, or weaken, the frame side rails.

During hoisting, do NOT damage the fuel tanks, the exhaust system, or the underbody.

Scheme 17

Scheme 18

Note. The front hoist pads must not contact the rocker panels, the front fenders, or the floor pan.

Position the front hoist pads under the front frame between the lower control arm and the frame pad.

Scheme 19

Note. The rear hoist pads must not contact the body rocker panels or the floor pan.

Position the rear hoist pads under the rear spring, just behind the hanger

Scheme 20

Position the front lift under the outer edge of the front suspension lower control arms.

Scheme 21

Position the rear lift under the axle housing tubes on each side of the differential.

Do not damage the stabilizer bar.

Jacking

When you are lifting a vehicle with a vehicle jack or a floor jack, block the wheels at the opposite end from which you are lifting. Use jack stands to provide additional support.

Scheme 22

Note. The floor jack pad must not contact rocker panel or the floor pan.

Position the floor jack pad under the frame rail pad.

Scheme 23

Position the floor jack pad under the center of the rear axle differential.

Do not damage the establisher bar.

Scheme 24

Position the jack under the rear spring hanger.

Jack Stands

When you support the vehicle with jack stands, place the jack stands under the frame, the front suspension crossmember, or the rear axle.