General Information Chevrolet Chevy Express G1500

Conversion - English/Metric

Conversion - English/Metric

Equivalents - Decimal and Metric

Equivalents - Decimal and Metric

Arrows and Symbols

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

Scheme 1

Special Tools Ordering Information

The special service tools shown in this service manual that have product numbers beginning with J, SA or BT are available for worldwide distribution from

OE Tool and Equipment Group

Kent-Moore

28635 Mound Road

Warren

MI, U.S.A

48092-3499

Phone: 1-800-345-2233 or 586-574-2332

Monday through Friday

8:00 am-7:00 pm Eastern Standard Time

Fax: 1-800-578-7375 or 586-578-7321

The TECH 2 scan tool and accessories can be purchased through

Dealer Equipment and Services

5775 Enterprise Dr.

Warren

MI, U.S.A

48092-3463

Phone: 1-800-GM-TOOLS or 586-574-2332

Monday through Friday

8:00 am-6:00 pm EST

Fax: 1-586-578-7205

Diagnostic Work Sheets

The GM Diagnostic Worksheet has been designed to improve communications between the service customer and the technician. The diagnostic worksheet can provide the technician with more information than the conventional repair order, since it is filled out by the service customer. Dealers in the US may contact Dealer Support Materials at 1-800-235-8521 and request Form Number DWS-01 to obtain these worksheets at no cost. Dealers may also access the DWD Store in Dealerworld and search for form DWS-01 or select Service Forms under Other Links and then select Diagnostic Worksheet (under Bulletin Information on use of Diagnostic Worksheet). Please limit your requests to a reasonable quantity.

Dealers

All U.S. Dealers participating in the GM Common Training Program can enroll through the GM Common Training System Website at https://www.gmcommontraining.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 GM Common Training should contact the GM Common Training help desk at 1-888-748-2686. 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 GM 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.gmcommontraining.com using the "Contact Us" button on the site and/or the GM 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 2

The vehicle identification number (VIN) plate is the legal identifier of the vehicle. The VIN plate (1) is located on the upper LH corner of the Instrument Panel and can be seen through the windshield from the outside of the vehicle

Vehicle Identification Number (VIN) System

VIN Derivative

All engines and transmissions are stamped or laser etched with a partial Vehicle Identification Number (VIN), which was derived from the complete VIN. A VIN derivative contains the following nine positions

Vin Derivative

A VIN derivative can be used to determine if a vehicle contains the original engine or transmission, by matching the VIN derivative positions to their accompanying positions in the complete VIN

Vin Derivative Equivalent

Scheme 3

The vehicle certification label displays the following assessments

1. The Gross Vehicle Weight Rating (GVWR)
2. The Gross Axle Weight Rating (GAWR) - Front and Rear
3. The vehicle's payload rating
4. The original equipment tire sizes and the recommended tire pressures

Gross vehicle weight (GVW) is the weight of the vehicle and everything it carries. Include the following items when figuring the GVW

1. The base vehicle weight factory weight
2. The weight of all vehicle accessories, like the winches or the plows
3. The weight of the driver and the passengers
4. The weight of the cargo

The gross vehicle weight must not exceed the Gross Vehicle Weight Rating.

The front gross axle weight rating (GAWR FRT) is the weight exerted on the front axle. The rear gross axle weight rating (GAW RR) is the weight exerted on the rear axle. The front and rear gross axle weights must not exceed the front and rear gross axle weight ratings.

The payload rating defines the vehicle's maximum allowable cargo load. The cargo load includes the driver and the passengers. The payload rating is based on the vehicle's factory installed equipment. Deduct from the payload rating the weight of accessories added to the vehicle after the final date of manufacture.

The vehicle may have a Gross Combination Weight Rating (GCWR). The Gross Combination Weight Rating refers to the total maximum weight of the loaded tow vehicle including driver and passengers and a loaded trailer.

The vehicle tires must be the proper size and properly inflated for the load the vehicle is carrying.

Scheme 4

The vehicle certification label displays the following assessments

1. The Gross Vehicle Weight Rating (GVWR)
2. The Gross Axle Weight Rating (GAWR) - Front and Rear
3. The vehicle's payload rating
4. The original equipment tire sizes and the recommended tire pressures

Gross vehicle weight (GVW) is the weight of the vehicle and everything it carries. Include the following items when figuring the GVW

1. The base vehicle weight factory weight
2. The weight of all vehicle accessories, like the winches or the plows
3. The weight of the driver and the passengers
4. The weight of the cargo

The gross vehicle weight must not exceed the Gross Vehicle Weight Rating.

The front gross axle weight rating (GAWR FRT) is the weight exerted on the front axle. The rear gross axle weight rating (GAW RR) is the weight exerted on the rear axle. The front and rear gross axle weights must not exceed the front and rear gross axle weight ratings.

Scheme 5

The vehicle certification label displays the following assessments

1. The Gross Vehicle Weight Rating (GVWR)
2. The Gross Axle Weight Rating (GAWR) - Front and Rear
3. The vehicle's payload rating
4. The original equipment tire sizes and the recommended tire pressures

Gross vehicle weight (GVW) is the weight of the vehicle and everything it carries. Include the following items when figuring the GVW

1. The base vehicle weight (factory weight)
2. The weight of all vehicle accessories, like the winches or the plows
3. The weight of the driver and the passengers
4. The weight of the cargo

The gross vehicle weight must not exceed the Gross Vehicle Weight Rating.

The front gross axle weight rating (GAWR FRT) is the weight exerted on the front axle. The rear gross axle weight rating (GAW RR) is the weight exerted on the rear axle. The front and rear gross axle weights must not exceed the front and rear gross axle weight ratings.

The payload rating defines the vehicle's maximum allowable cargo load. The cargo load includes the driver and the passengers. The payload rating is based on the vehicle's factory installed equipment. Deduct from the payload rating the weight of accessories added to the vehicle after the final date of manufacture.

The vehicle may have a Gross Combination Weight Rating (GCWR). The Gross Combination Weight Rating refers to the total maximum weight of the loaded tow vehicle (including driver and passengers) and a loaded trailer.

The vehicle's tires must be the proper size and properly inflated for the load the vehicle is carrying.

Scheme 6

The vehicle certification label displays the following assessments

1. The Gross Vehicle Weight Rating (GVWR)
2. The Gross Axle Weight Rating (GAWR) - Front and Rear
3. The vehicle's payload rating
4. The original equipment tire sizes and the recommended tire pressures

Gross vehicle weight (GVW) is the weight of the vehicle and everything it carries. Include the following items when figuring the GVW

1. The base vehicle weight factory weight
2. The weight of all vehicle accessories, like the winches or the plows
3. The weight of the driver and the passengers
4. The weight of the cargo

The gross vehicle weight must not exceed the Gross Vehicle Weight Rating.

The front gross axle weight rating (GAWR FRT) is the weight exerted on the front axle. The rear gross axle weight rating (GAW RR) is the weight exerted on the rear axle. The front and rear gross axle weights must not exceed the front and rear gross axle weight ratings.

Scheme 7

Located on the VIN plate, the VIN provides detailed engine identification and code information by liter and by the engine code letter.

Scheme 8

The engine unit number or date code is either laser etched or stamped into the engine block.

Scheme 9

All engines are stamped with an eight digit engine identification number.

Scheme 10

Scheme 11

Engine and Transmission Usage

Engine and Transmission Usage - G Van Applications

Scheme 12

Scheme 13

An identification tag is attached to the front half of the transfer case. The tag provides the following information

1. Model number (1)
2. Manufacturer (2)
3. Part Number (3)
4. Serial Number (4)

The information on this tag is necessary for servicing the transfer case. If the tag is removed or becomes dislodged during service operations, keep the identification tag with the unit.

Scheme 14

Front axle identification information is stamped on the top of the differential carrier assembly. The information includes the following

1. Broadcast code (1)
2. Supplier code (2)
3. Date built (3)
4. Shift built (4) (Optional for 8.25 inch and 9.25 inch axles)
5. Hour built (5)

In order to verify reports made on the differential case assembly, include full code letters and build date numbers.

Scheme 15

Rear axle identification information is stamped on the right side axle tube near the differential housing. The information includes the following

1. Broadcast code (1)
2. Build Source (2)
3. Build date (3) - Julian date
4. Shift built (4)

In order to verify reports made on the rear axle assembly, include full code letters and build date numbers.

Scheme 16

The Service Parts Identification Label aids the service personnel in identifying the parts and options originally installed on the vehicle.

Scheme 17

The Service Information Parts ID label is located on the right front door of the vehicle.

RPO Code List

The production/process codes provide the description of the Regular Production Options (RPOs). The RPO list is printed on the Service Parts Identification Label.

RPO Code List

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 18

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

Prevailing Torque Fasteners

Prevailing torque fasteners create a thread interface between the fastener and the fastener counterpart in order to prevent the fastener from loosening.

All Metal Prevailing Torque Fasteners

These fasteners accomplish the thread interface by a designed distortion or deformation in the fastener.

Nylon Interface Prevailing Torque Fasteners

These fasteners accomplish the thread interface by the presence of a nylon material on the fastener threads.

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 19

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.

Abbreviations and Meanings

Abbreviations and Meanings

Registered and Non-Registered Trademarks

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

Registered and Non-Registered Trademarks

Key Identification and Usage

The lock cylinder keyway is designed so that other model keys will not enter a current model lock cylinder. A single key is used for all locks on the vehicle.

The key identification is obtained from the four-character key code stamped on the knockout portion of the key head. Knock the plugs out of the key head after code numbers have been recorded. The code list, available to owners of key cutting equipment from equipment suppliers, determines the lock combinations from the code numbers.

Cutting Keys

After the code has been determined from the code list or the key code diagram, perform the following steps

1. Cut a blank key to the proper level of each of the tumbler positions.
2. Inspect the key operation in the lock cylinder.

Replacement Lock Cylinders

New lock cylinders (except ignition lock cylinders) are available from the service parts warehouse with new lock cylinder locking bars. The tumblers are also available and must be assembled into the cylinder as recommended. For additional information, refer to the following.

Lock Cylinder Tumbler Operation

All lock tumblers are shaped alike with the exception of the notched position on one side. As the key is inserted into the lock cylinder, the tumblers are lowered to the correct height so that notches on each tumbler are at the same level. When the notches on all six tumblers line up, two small springs push the side bar into the notches, allowing the cylinder to turn in the cylinder bore. Five types of tumblers are used in making the lock combinations, and each is coded and stamped with a number between 1 and 5.

Tools Required

J 41340 Ignition Lock Holding Fixture. See Special Tools and Equipment .

Scheme 20

1. Determine the tumbler numbers/arrangement: Place the tip of the key directly over the tip of the illustrated key. Inspect that the diagram outlines the key. Starting with position 1 (open end of cylinder), find and record the lowest level (tumbler number) that is visible. Repeat the previous step for positions 2-10.
2. Starting with position 1, insert the tumblers (4) into their corresponding slots in the coded order.
3. Using your fingers, pull out the side bar (3) until the tumblers fall completely into place.
4. Insert one tumbler spring (2) above each tumbler (4).
5. Lubricate the tumblers using Superlube® GM P/N 12346241 or equivalent.
6. Insert the spring retainer (1) prongs into the slots at the end of each cylinder.
7. Press down the retainer (1) until fully seated in the depression.
8. Inspect for proper tumbler installation: Hold the spring retainer (2) in position. Insert the key (1) into the cylinder. The side bar (3) should drop down flush with the cylinder diameter if properly installed. Disassemble and assemble properly as needed.
9. Remove the key.
10. Secure the cylinder in the J 41340 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Inspect that the spring retainer is facing up and positioned directly under the punch slots. Push the cylinder into the J 41340 until butted with the cylinder bezel. See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Tighten the holding screw.
11. Stake the bezel end of the retainer in place: Hold the flat side of the punch, part of J 41340 , squarely against the face of the cylinder bezel. See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Stake the lock cylinder metal over the retainer corners.
12. Stake the other end of the retainer: Remove the punch, part of J 41340 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Rotate the punch, part of J 41340 , 180 degrees. See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Hold the punch, part of J 41340 , squarely against the end of the punch slot on. See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . J 41340 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) . Stake the metal over the other end of the retainer.
13. Loosen the holding screw.
14. Remove the cylinder from the J 41340 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g1500/1996-2012/remont/hoistjack/#general-information) .
15. Inspect that the retainer is properly staked. Restake as needed.
16. Lubricate the cylinder retainer slot.
17. Insert the following parts into the cylinder retainer slot: The retainer spring (2) The retainer (3)
18. Lubricate the following parts with GM P/N 12345996 or equivalent as needed: The detent pins (1) The cylinder retainer (3)

Side Door Lock Cylinder Coding

The side door lock cylinder has five snap-in tumblers. The number 1-5 positions (beginning closest to the cylinder head) is a brass retainer tumbler. The 6-10 positions are standard tumbler positions. Therefore, only the 6-10 positions are required.

Lifting and Jacking the Vehicle

Note. Perform the following steps before beginning any vehicle lifting or jacking procedure: Remove or secure all of the vehicle's contents in order to avoid any shifting or any movement that may occur during the vehicle lifting or jacking procedure. The lifting equipment or the jacking equipment weight rating must meet or exceed the weight of the vehicle and any vehicle contents. The lifting equipment or the jacking equipment must meet the operational standards of the lifting equipment or jacking equipment's manufacturer. Perform the vehicle lifting or jacking procedure on a clean, hard, dry, level surface. Perform the vehicle lifting or jacking procedure only at the identified lift points. DO NOT allow the lifting equipment or jacking equipment to contact any other vehicle components. Failure to perform the previous steps could result in damage to the lifting equipment or the jacking equipment, the vehicle, and/or the vehicle's contents.

Use only the prescribed lift points when elevating the vehicle.

Scheme 21

The jack and hoist lift points for the front of the vehicle are located between the front body mounts and the transmission crossmember. The jack and hoist lift points for the rear of the vehicle are located at the front hangers for the rear springs.

The front end lift points for the floor jack are at the following locations

1. Beneath the lower control arms, inboard from the shock absorber mounts
2. Beneath the center of the front crossmember

The rear end lift points for the floor jack are at the following locations

1. Beneath the axle housing, inboard from the shock absorber mounts
2. Beneath the axle differential

Whenever the vehicle is lifted using a jack or a floor jack, observe the following precautions

1. Chock the wheels at the end of the vehicle opposite the end being lifted
2. Use jack stands for support. Place jack stands at the any of the following locations: Beneath the frame Beneath the front suspension crossmember Beneath the axle

When removing major components from the vehicle while the vehicle is on a hoist, chain the vehicle frame to the hoist pads in order to prevent tip-off.

Note. When jacking or lifting a vehicle, do not allow the lift pads to contact any of the following parts: The catalytic converter The brake lines The brake cables The fuel lines The accelerator cables The transmission shift cables Lift pad contact may damage the parts. Lift pad contact may cause unsatisfactory vehicle performance.

Strategy Based Diagnosis

The goal of Strategy Based Diagnostics is to provide guidance when you create a plan of action for each specific diagnostic situation. Following a similar plan for each diagnostic situation, you will achieve maximum efficiency when you diagnose and repair vehicles. Although each of the Strategy Based Diagnostics boxes is numbered, you are not required to complete every box in order to successfully diagnose a customer concern. The first step of your diagnostic process should always be, verify the Customer Concern box. The final step of your diagnostic process should be Repair and verify the Fix box 7. Refer to the following chart for the correct Strategy Based Diagnostics.

Scheme 22

Special Tools

Special Tools Illustration Tool Number/ Description J 41340 Ignition Lock Cylinder Staking and Holding Fixture

Scheme 23

See also:
• Special Tools and Equipment