CAMPAIGN: AXLE SHAFT END PLAY CHECKING PROCEDURE. GMC Truck Caballero 1980

For 1990-2009 cars

# CAMPAIGN: AXLE SHAFT END PLAY CHECKING PROCEDURE

1978-1980 CABALLERO

This notice is sent to you pursuant to an agreement of settlement between the Department of Transportation and General Motors Corporation.

In April 1983, the National Highway Traffic Safety Administration (NHTSA) made an initial determination that a defect which relates to motor vehicle safety exists in certain 1978-80 GMC Caballero vehicles. Specifically, the NHTSA determined, at that time, that some of these vehicles "may be manufactured with rear axle shafts with thin end buttons" and that "this condition may result in disengagement or separation of the axle shaft and wheel assembly from the vehicle, which could lead to loss of vehicle control, accidents, injuries, death or property damage."

Despite General Motors continuing disagreement with that preliminary finding, General Motors desires to resolve any concerns in the minds of our customers and to address NHTSA's continuing concerns with respect to the possibility of future rear axle separations involving axles produced at GM's Buffalo axle plant. Accordingly, the dealers are required to inspect and determine if the owner's vehicle has an axle produced at the Buffalo axle plant. If so, make the rear axle measurements and repairs or modify as covered in the procedures which are listed.

#### Vehicles Involved

Involved are certain 1978-80 GMC Caballero vehicles built at the following assembly plants.

Assembly Up to And Year Plant Beginning Including ---- ----- --------- ----------

1978,1979 Doraville 8D500001 AD501317 & 1980 Leeds 8K500001 AK501967 Arlington 8R500001 AR500772 Fremont 8Z500001 AZ500647

#### Dealers Responsibility

Dealers are to service all vehicles subject to this field procedure at no charge to the owner, regardless of mileage, age of vehicle, or ownership, from this time forward.

In addition, whenever a vehicle subject to this field procedure is taken into your dealership for service or into your used car inventory, you should be sure that this procedure or any campaign required by CRIS (Computerized Recall Information System) or other divisional information is completed prior to release or resale of the vehicle.

#### SERVICE PROCEDURE

1. Raise the vehicle on a hoist. Locate the axle identification information stamped on the right front inboard side of the axle tube. Refer to Figure No. I. It may be necessary to wire brush the area to make it legible.

2. If the manufacture code indicates a "C" as shown in Figure No. 1, go to Step 3 of this procedure. If other than a "C" proceed to Setp 13.

3. If the vehicle has less than 20,000 miles go directly to Step 8.

If the vehicle has greater than 20,000 miles, mount a dial indicator on the axle housing behind either rear wheel. Rest the indicator point against the back side of the wheel or the edge of the brake drum.

4. Measure the end play of each axle shaft by grasping the tire with both hands and pushing outboard until axle shaft is felt to bottom Zero indicator. Refer to Figure No. 2.

5. Again grasp the tire with both hands and pull inboard until axle shaft is felt to bottom. Read the indicator, making certain that the reading is within the range of the indicator. Record the indicator reading of each rear axle. Refer to Figure No. 2.

6. The readings obtained in Step 5 should be compared with the specifications in Chart 1.

CHART I Maximum Allowable End Play for Either Axle Shaft

Mileage Perform Step 8 If End Play Is: ------- ------------------------------ 20,000 to 30,000 Greater than .030 30,000 to 45,000 Greater than .040 45,000 or Over Greater than .055

7. If the end play reading of both axle shafts EQUALS or is LESS than the end play specification in Chart I, at the mileage indicated. no additional checking is required. Proceed to Step 13.

If the end play reading of either axle shaft EXCEEDS the end play specification in Chart I, at the indicated mileage, the following steps should be performed.

8. Remove the axle carrier inspection cover and drain the lubricant.

9. Each axle shaft button thickness must be measured using the Special Axle Button Gage Tool provided. In order to measure button thickness, the axle shafts must be pushed fully inboard and the "C" lock must be rotated so that opening faces rearward to allow access for the gage. See Figures No. 3 and No. 4. The button thickness must be checked using both ends of the gaging tool. Refer to Chart II to determine the action required.

10. If necessary, the axle shaft and the differential pinion shaft should be replaced using the procedure in the applicable service manual. For part numbers, refer to "Parts Information" section of this bulletin.

11. After completing above steps, verify that axle shaft end play is less than the maximum allowed in Chart III. If it is not, determine cause of end play, if possible, and contact your Zone Office for instruction.

CHART III

Maximum Allowable End Play for Either Axle Shaft After Performing Above Procedure Mileage Standard Axle Limited Slip ------- ------------- ------------ To 45,000 .040 .065 Over 45,000 .055 .085

12. Install the axle carrier cover using a new cover gasket and fill housing with the proper lubrication. Lower hoist.

13. Raise hood to install a Completion Identification Label on the radiator core support.

Each vehicle modified in accordance with the instructions outlined in this service procedure will require an identification label. Each label provides a space to include the five (5) digit dealer code of the dealer performing the service. This information may be inserted with a type- writer or ballpoint pen. Install the label on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. Apply label only on a clean, dry surface. Close hood.

PARTS INFORMATION

VERY FEW VEHICLES WILL REQUIRE PARTS (1 IN EVERY 200 VEHICLES INSPECTED). THEREFORE, LIMIT THE NUMBER OF PARTS BEING ORDERED TO PREVENT A PARTS SHORTAGE CONDITION. To ensure that parts will be obtained as soon possible, they should be ordered from WDDGM on a C.I.O. order with NO special instruction code, but order on an advise code (2).

CHART II Pinion Shaft and Axle Shaft Replacement

Axle Shaft Button Thickness

Mileage Greater Than .190" .160"-.190" Less Than .160" ------- ------------------ ----------- ---------------- 0 to 20,000 Replace Pinion Replace Pinion Replace Pinion Shaft Shaft & Axle Shaft 20,000 to 75,000 No Part Replace Pinion Replace Pinion Replacement Shaft & Axle Shaft Over 75,000 No Part No Part Replace Pinionn Replacement Replacement & Axle Shaft

Description Part Number Quantity ----------- ----------- --------- Axle 551818 As Required Pinion Shaft 22507586 1 Use for Std. or G80 Limited Slip

Differential Cover Gasket 551651 1

Lubricant 1052271 1-3/4 qt.

Lubricant 1052358 4 oz. Additive (Limited Slip Only)

#### Warranty Information

Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed.

Labor *Time Trouble Number Description Allowance Code ------ ----------- ---------- ----

V247000 Inspect axle code, no further 0.3 hr. 96 action required.

V247100 Inspect axle code and check end play. 0.3 Hr. 96

V247200 Inspect axle code, check end play and 0.5 Hr. 96 button thickness.

V247300 Inspect axle code, check end play and 0.7 Hr. 96 button thickness. Replace one or two axle shafts and or pinion shaft.

*For dealer to receive Administrative Time Allowance associated with this service, add 0.1 hour to the Lbor Operation Time Allowance.

Dear GMC Truck Owner

This notice is sent to you pursuant to an agreement of settlement between the Department of Transportation and General Motors Corporation.

In April 1983, the National Highway Traffic Safety Administration (NHTSA) made an initial determination that a defect which relates to motor vehicle safety exists in certain 1978-80 GMC Caballero vehicles. Specifically, the NHTSA determined, at that time, that some of the vehicles "may be manufactured with rear axle shafts with thin end buttons" and that "this condition may result in disengagement or separation of the axle shaft and wheel assembly from the vehicle, which could lead to loss of vehicle control accidents, injuries, death or property damage."

Despite General Motors continuing disagreement with that preliminary finding, General Motors desires to resolve any concerns in the minds of our customers and to address NHTSA's continuing concerns with respect to the possibility of future rear axle separations involving axles produced at GM's Buffalo axle plant. Accordingly, you are encouraged to take your vehicle to your dealer for inspection to determine if the vehicle has an axle produced at our Buffalo axle plant. If so, the dealer will make rear axle measurements. If the conditions specified in our dealer bulletin are present dealers will replace or modify affected axle components. These inspections, measurements and replacements or modifications will be performed free of charge to you.

Instructions for this inspection and any additional work have been furnished to your dealer. It is estimated that parts will be available on December 28, 1984.

Your dealer is best equipped to ensure your vehicle is inspected as promptly as possible. However, if you take your vehicle to your dealer on the agreed service date, and they do not perform the work on that date or within five days, we recommend you contact the nearest GMC Truck Zone Office, either in person or by telephone, for assistance. The Zone Office will assist you and the dealer in getting the appropriate work completed. The locations and telephone numbers of the Zone Offices are listed in your Owners Manual. After contacting your dealer and the Zone Office, if you are still not satisfied that we have done our best to complete the work without charge within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street S.W., Washington, D.C., 20590, or call 1-800-424-9393 (Washington, D.C. residents may call 426-0123).

The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in performing the work in the shortest time. If you have sold or traded your vehicle, please let us know by completing the postage-paid owner reply card and returning it to us.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.