All Models Except Escape
WARNING:
On vehicles with electronic air suspension, suspension system must be disabled prior to hoisting or jacking. See DISABLING ELECTRONIC AIR SUSPENSION under MAINTENANCE.
- Raise and support vehicle. Remove drive wheels. Reinstall lug nuts. Rotate shaft by turning brake drum or rotor. Use dial indicator to measure runout. If runout at front and/or center of shaft exceeds .035" (.89 mm), replace drive shaft.
- If runout at front and/or center is okay but rear runout exceeds .035" (.89 mm), rotate and mark high spot on drive shaft. Scribe index mark on drive shaft. Disconnect drive shaft at rear flange.
- Rotate shaft 180 degrees. Reconnect shaft. Repeat runout check. If runout is now less than .035" (.89 mm), but vibration persists, go to step 5. If runout still exceeds .035" (.89 mm), rotate shaft and scribe another mark on high spot of shaft.
- If the 2 marks made are approximately 1" (25 mm) apart, replace drive shaft. If the 2 marks made are approximately 180 degrees apart, replace companion flange or yoke. See Fig 1.
- If no faults were found, or have been repaired, but still vibrates, place 4 marks approximately 6" forward of weld at rear end of shaft, spaced equally around shaft. Label marks 1, 2, 3 and 4. Place screw-type hose clamp so clamp head is in No. 1 position. Start engine. Spin drive shaft at road speed.
- If there is little or no change, move clamp head to No. 2 position, and repeat test. Continue procedure until vibration is at lowest level. If no difference is noted with clamp head moved to all 4 positions, vibration may not be drive shaft imbalance.
- If vibration is lessened but not completely gone, place 2 clamps at that point, and run test again. Combined weight of clamps in one position may increase vibration. If vibration is increased, rotate clamps about 1/2" (13 mm) apart, above and below best position, and repeat test.
- Continue to rotate clamps as necessary, until vibration is at lowest point. If vibration level is still unacceptable, leave rear clamp(s) in position and repeat procedure at front end of drive shaft. If vibration cannot be reduced to acceptable range using this procedure, replace drive shaft.