Driveshaft Balance & Rear Springs & Axle Information
Driveshaft Balance1. Raise the vehicle on a twin post hoist.
2. Start the engine, engage the transmission and run up to vibration speed.
NOTE: Observe the level of vibration in the seat and steering wheel.
3. Have an assistant install one hose clamp at the rear of the driveshaft. Position the clamp with the screw head lined up with the existing balance weights on the driveshaft.
4. Start engine and run up to vibration speed. If the vibration got worse, rotate the clamp 180 degrees. Continue the procedure of rotating at 90 degree increments until all four (4) quadrants have been evaluated. Choose the best position and tighten clamp.
5. If vibration is still present, install a second clamp in the same position as the one installed in Step 4.
6. If vibration increases, scribe a line on the driveshaft at the screwhead locations.
7. Rotate one (1) clamp a 1/2" clockwise and the other 1/2" counterclockwise. Move the clamps further apart or closer together as required to "FINE TUNE" the system.
Rear Springs
1. Make sure rear springs are the six leaf design.
2. If not, install two (2) new six leaf springs, (D6UZ-5560-D).
Rear Axle
1. If the condition is still present after all the above sections have been completed, road test the vehicle to determine if the correct driveline angle is present or a new ring and pinion assembly is required.
2. Drive vehicle about 10-12 miles (16-19 kilometers).
3. With the transmission in overdrive for AOD transmission or in drive for C6 transmissions, accelerate to 50 MPH (80 km/h). Slowly increase the speed to 65 MPH (105 km/h) noting at what speed the noise and vibration occur.
4. Shift into neutral and coast down to 50 MPH (80 km/h). Observe whether or "boom" noise is present and at what speed.
5. If "boom" is only present in drive, measure the angle between the driveshaft and axle. If greater than 2 degrees, shim the axle at the spring seats to achieve a 1 degree angle.
6. Road test the vehicle. If the "boom" is still present, install a special "low" pitch line runout (PLRO) rear axle ring and pinion set. Refer to the following ring and pinion application chart.
RING AND PINION APPLICATION CHART
Axle
Application Type Ratio Part Number
1983-86 9" 3.50:1 E3UZ-4209-D
1987 8.8" 3.55:1 E7TZ-4209-B
NOTE: A new balanced half round circular flange, (E3UZ-4851-A) must be installed in 1983-86 units along with the 9" ring and pinion gear set.
NOTE: A "boom" noise during a neutral coast indicates an imbalanced driveline. Refer back to the "Driveshaft Section" for diagnosis.
PART NUMBER PART NAME CLASS
E6UZ-4602-H Driveshaft C
E6UZ-4602-J Driveshaft C
E6UZ-4602-K Driveshaft C
E7UZ-4602-U Driveshaft C
E8UZ-4602-C Driveshaft C
D6UZ-5560-D Rear Spring C
E3UZ-4209-D Ring and Pinion C
E7TZ-4209-B Ring and Pinion B
E3UZ-4851-A Flange C
OTHER APPLICABLE ARTICLES: 86-15-15
WARRANTY STATUS: Eligible Under Basic Warranty and Powertrain Warranty Coverages
OPERATION: 880717A - Wheel and Tire Section (Includes check runout and balance all four wheels and tire assemblies)
TIME: 1.6 Hrs.
OPERATION: 880717B - Body to Chassis Groundout Section
TIME: 0.2 Hr.
OPERATION: 880717C - Exhaust System Section
TIME: 0.5 Hr.
OPERATION: 880717D - Driveshaft and Road Test Sections
TIME: 1.1 Hrs.
OPERATION: 880717F - Driveshaft Balance Section
TIME: 1.4 Hrs.
OPERATION: 880717G - Rear Spring Section
TIME: 1.4 Hrs. - Both
OPERATION: 880717H - Rear Axle Section
TIME: 3.5 Hrs. - Standard Axle
4.4 Hrs. - Limited Slip Axle
DLR. CODING: Basic Condition
Part No.: Code:
Wheel and Tire Section 1007 67
Body to Chassis
Groundout Section 7000396 35
Exhaust System Section 5260 36
Driveshaft and Road Test
Sections 4602 67
Driveshaft Balance
Section 4602 67
Rear Spring Section 5560 53
Rear Axle Section 4209 53
NOTE: The only components that are eligible under Powertrain Coverage are part numbers 4209 and 4602.