Driveshaft Balancing

Vibration shudder that is noticeable either on fast acceleration, when coasting, or when using the engine for braking may be caused by the rear axle housing (4010) being loose on the rear springs (5560) , improper tire balance, improper driveline installation, or driveline balance.

If detailed parts of the driveshaft (4602) are replaced and shaft vibration is encountered after installation, disconnect the shaft at the driveshaft slip yoke (4841) . Rotate the driveshaft slip yoke 180 degrees. Reconnect the driveshaft to the driveshaft slip yoke . If the vibration persists, disconnect the driveshaft at the rear axle universal joint flange (4851) . Rotate the rear axle universal joint flange 180 degrees and reconnect the driveshaft to the rear axle universal joint flange .

If rotating the driveshaft 180 degrees does not eliminate vibration, the driveshaft may be balanced, using the following procedure. Two people are required to perform this operation; one in the vehicle, and one under the vehicle making adjustments.

1. Raise the vehicle on a twin-post hoist so that both the front and rear axle housings are safety supported with all wheels (1007) free to rotate.

2. With the transmission in gear, increase the vehicle speed to the maximum vibration level. Note and record the speedometer speed of this vibration period as a baseline speed.

3. Check the attachment of all U-joint bearing caps of the driveshaft to the driveshaft slip yoke , driveshaft slip yokes for improper installation or damaged U-joint bearing cap locating lugs. All yokes with worn, shaved, or damaged locating lugs must be replaced.

4. Check the driveshaft for correct phasing.

    WARNING: DO NOT WEAR LOOSE CLOTHING THAT COULD GET CAUGHT ON THE ROTATING SHAFT.

5. With the transmission in gear, run the vehicle with the driveshaft rotating at a speedometer speed of 65-80 km/h (40-50 mph), carefully bring a crayon, piece of chalk, or colored pencil up until it just barely contacts the rear end, center and front end of the driveshaft . The chalk marks will indicate the heavy side of the driveshaft . Use caution when checking the driveshaft near the balance weights to prevent injury to the hands.

6. Install two screw-type hose clamps on the driveshaft so that their heads are located 180 degrees from the chalk mark, starting at the rear axle universal joint flange end of the driveshaft . Tighten the clamps and cut off the excess band from the clamps.
   
   
   
   

7. Run the vehicle up to the baseline speed. If vibration is still evident, rotate the clamps approximately 45 degrees away from each other and test for correction of vibration.

8. If necessary, continue to rotate the clamps apart in smaller increments until the vibration is eliminated or begins to be reduced.

9. If the vibration is not completely eliminated, repeat the foregoing procedure and balance the front end of the driveshaft , checking for elimination or reduction in the vibration level.
   
   
   
   

10. To completely eliminate the driveline vibration, it may be necessary to balance the coupling shaft, following the same procedure as for the driveshaft . To prevent overheating, do not run the vehicle on the hoist for an extended period.

11. Remove the vehicle from the hoist and road test.