Drive Shaft RUNOUT
WARNING: This page is about a different car, the 2002 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.
Driveline vibration exhibits a higher frequency and lower amplitude than does high-speed shake. Driveline vibration is directly related to the speed of the vehicle and is usually noticed at various speeds. Driveline vibration can be perceived as a tremor in the floorpan or heard as a rumble, hum or boom.
Driveline vibration can exist in all drive modes, but may exhibit different symptoms depending upon whether the vehicle is accelerating, decelerating, floating or coasting. Check the driveline angles if the vibration is particularly noticeable during acceleration or deceleration, especially at lower speeds. Driveline vibration can be duplicated by supporting the axle on a hoist or jack stands, though the brakes may need to be applied lightly to simulate road resistance.
- Inspect the drive shaft(s) for damage, undercoating or incorrectly seated universal joints. Rotate the drive shaft slowly by hand and feel for binding or end play in the "U" joint trunnions.
- Check the index marks (Yellow paint) on the rear drive shaft and the pinion flange. If the marks are not aligned, disconnect the drive shaft and realign the marks as close as possible. Remove and inspect the slip yoke splines for any galling, dirt, rust, or incorrect lubrication. Clean the drive shaft or install NEW "U" joints as necessary. Install a NEW drive shaft if damaged. See REMOVAL & INSTALLATION .
- After any correction or component replacement, recheck for the vibration at the road test speed. If the vibration is gone, reinstall the tires and wheels and test drive. If the vibration persists or the drive shaft passes visual inspection, go to next step.
- Using a dial indicator, measure the drive shaft at the front, center, and rear. Rotate the drive shaft using a brake drum or brake disc rotor. If the runout exceeds 0.035" (0.89 mm) at the front or center, install a NEW drive shaft. If the front and center is within specification, but the rear runout is not, index mark the rear runout high point and go to next step. See Fig 1 . If the runout is within specification at all points, go to step 7 .
- Index mark the drive shaft to the pinion flange. Disconnect the drive shaft and rotate it 180 degrees. Reinstall the drive shaft. Recheck the runout at the drive shaft rear. If the runout is still over 0.035" (0.89 mm), mark the high point and go to next step. If the runout is within specification, check for the vibration at the road speed. If the vibration is still present, go to step 7 .
- Excessive drive shaft runout can originate in the drive shaft itself. To find the source, compare the 2 high points previously determined. If the index marks are close together, within 0.98" (25 mm), the drive shaft is eccentric and should be replaced. See Fig 2 . See REMOVAL & INSTALLATION . Recheck the drive shaft at the road test speed. If the marks are on opposite sides of the drive shaft, 180 degrees apart, the slip yoke or pinion flange is responsible. Check the pinion flange runout. See appropriate DIFFERENTIALS & AXLE SHAFTS article.
- To balance the drive shaft, install one or 2 hose clamps on the drive shaft, near the ends. Position of the hose clamp head(s) can be determined through trial and error.
- Mark the rear of the drive shaft into 4 equal sectors, and number the marks 1 through 4. Install a hose clamp on the drive shaft with its head at position No. 1. See Fig 3 . Check for vibration at road speed. Recheck with the clamp at each of the other positions to find the position that shows minimum vibration. If 2 adjacent positions show equal improvement, position the clamp head between them.
- If the vibration persists, add a second clamp at the same position and recheck for vibration. See Fig 4 . If no improvement is noted, rotate the clamps in opposite directions, equal distances from the best position. Separate the clamp heads about 0.51" (13 mm) and recheck for vibration at the road speed.
- Repeat the process with increasing separation until the best combination is found or the vibration is reduced to an acceptable level. See Fig 5 . Install the wheels and road test (vibration noticeable on the hoist may not be evident during the road test). If the vibration is still not acceptable, install a NEW drive shaft. If the vibration is still not acceptable, see appropriate DIFFERENTIALS & AXLE SHAFTS article for differential case and ring gear runout checks.