EI07266 - Vehicle/Tire Vibration, P275/55R20 Goodyear, LT245/75R16, P265/70417, P245/70R17 (Engineering Information)

This bulletin is being revised to update the affected models and tire RPOs and revise the diagnostic steps. Please discard Corporate Bulletin Number 07-03-10-013A (Section 03 -- Suspension).

Some customers may comment on a vehicle/tire vibration.

Important:  For vehicles equipped with RPO QSS (P275/55R20), this bulletin only applies to Goodyear tires. If the vehicle is equipped with RPO QSS -- Bridgestone tires, disregard this bulletin.

GM Engineering is attempting to determine the root cause of reported tire vibrations on vehicles equipped with P275/55R20 (Goodyear), LT245/75R16, P265/70R17 or P245/70R17 tires. GM has a need to obtain information during diagnosis and BEFORE repair. This information will be used by engineering to "root cause" the customer's concern and develop/validate a field fix.

If the customer's concern cannot be duplicated, disregard this bulletin. If the customer's concern can be duplicated, complete the following steps. Be sure to note the following information on the repair order:

1. Verify that the VIN and mileage listed on the repair order is accurate.
2. Describe the customer's concern (i.e. shake, buzz, roughness, tingling). Note when (mph, idle, accel, decel, etc) and where (steering column, seat, etc) the vibration is felt.
3. Document the tire size and manufacturer of the tires currently on the vehicle.
4. Inspect the following components to verify that they are in good working condition. Note any "faults" on the repair order:

•	tire/wheel assemblies -- Verify the presence of wheel weights and PSI of tires.

•	steering components

•	suspension components

5. Select a smooth, level road and slowly accelerate the vehicle up to highway speed.
6. Observe the vehicle for disturbances that match the customer's description and note the following conditions:

•	Vehicle speed

•	Engine RPM

•	Transmission gear range and specific gear

7. Does the disturbances match the customer's description? (Refer to Symptoms -- Vibration Diagnosis and Correction, found in SI).

•	NO -- continue to diagnose and repair the vibration not related to the tire and wheel assembly. Fax the completed repair order (front and back) to: 248-685-6140 -- Attn: Kevin Kelly

•	YES -- proceed with Step 8.

Important:  Before proceeding with step 8, the vehicle must be driven for at least 10 miles, any "load" removed from the vehicle and PSI checked to Placard prior to checking Roadforce Variation.

8. Using the HUNTER GSP9700 Roadforce/Balancer, measure the roadforce variation of each tire/wheel assembly. Guidelines for acceptable Roadforce Variation can be found in SI -- refer to bulletin 00-03-10-006C. Also, with the original balance weights still installed, measure the inboard and outboard imbalance. Record the findings on the RO.
9. Record on the repair order the DOT number found on the rim flange of the tire.
10. PRIOR to making any repairs, contact the engineer listed below with information from your diagnosis. The engineer will provide direction to repair the customer's concern. For vehicles located in SE Michigan, the engineer may need to physically inspect the vehicle.

If necessary, leave a message with the following information:

Important: If the engineer is unable to return your call within one (1) hour, proceed with diagnosis and repair according to SI. Fax the complete repair order (front and back) to 248-685-6140. If tire(s) are replaced, include all findings when tire(s) are sent back through the Global Tire Return Process.

Important:  For vehicles not repaired using this bulletin, use the appropriate labor operation found in the Labor Time Guide.

For vehicles in which the customer's concern was due to a tire vibration, submit the warranty claim using the following labor operation.

In addition, for all cases in which a tire was replaced, also claim the corresponding Manufacturers labor operation/time found in the Labor Time Guide. Note, labor times include time to balance.