Inspection of the Driveline

4700 mm 41.01.001

    Caution: Due to the extreme load occurring at high-speed rotation, a loose or broken capscrew at any point in the driveline will weaken the driveline connection, which could eventually result in serious vehicle damage. Do not over-tighten bearing-cap capscrews or yoke-strap capscrews.

  1. Park the vehicle on a level surface, shut down the engine, and apply the parking brake. Chock the tires.
  2.  For driveline universal joints with bearing caps, tighten bearing-cap capscrews 43 lbf·ft (49 N·m). See Fig., item 1. For RPL series universal joints, tighten bearing-cap capscrews 125 lbf·ft (169 N·m). See Fig.. For driveline universal joints with yoke straps, tighten yoke-strap capscrews 125 lbf·ft (169 N·m). See Fig..

    1. Self-Locking Capscrew

    2. Adhesive Band

    Fig. 1, Meritor U-Joint Fasteners for Bearing Caps

    Fig. 2, Meritor RPL Series U-Joint

    Note: All fasteners are not shown.

    1. Transmission

    2. Transmission Output-Shaft End-Yoke (yoke-strap type)

    3. U-Joint Assembly

    4. Bearing Cap Self-Locking Capscrew

    5. Bearing Cap

    6. U-Joint Cross

    7. Bearing Cup (for yoke strap)

    8. Yoke Strap and Capscrew

    9. Slip-Joint Assembly

    10. Sleeve-Yoke (bearing-cap type)

    11. Dust Cap

    12. Splined Stub Shaft

    13. Driveshaft Tube

    14. Tube-Yoke (bearing-cap type)

    15. Axle Input-Shaft End-Yoke (yoke-strap type)

    16. Rear Axle

    Fig. 3, Components of a Basic Driveline

  3. Check the driveline yokes for cracks, and check end-yokes for looseness. See Fig.. Have any cracked yokes replaced by an authorized Western Star dealer. If any end-yoke can be moved in or out on its shaft, or can be rocked on its shaft, take it to an authorized Western Star dealer for service.
  4. Check U-joint assemblies for wear by moving the driveshaft up and down, and from side to side. If any movement of the U-joint cross in the bearings can be felt or seen, have the U-joint assembly replaced.
  5. Check if the midship bearing and mounting are loose or have deteriorated, by attempting to move the driveshaft up and down, and from side to side. If the bearing is loose on its shaft, or rattles, have it replaced. If the bearing mount is loose on the frame, have your Western Star dealer tighten the mounting fasteners to the proper torque value. Have the midship bearing assembly replaced if the rubber cushion is deteriorated or oil-soaked.
  6. Check slip joints for spline wear by moving the sleeve-yoke and splined shaft back and forth. See Fig.. If the slip joint can be twisted in a clockwise or counterclockwise movement greater than 0.007 inch (0.18 mm), have both the sleeve-yoke and the splined shaft replaced.

    Attempt to move the sleeve-yoke and splined shaft back and forth.

    Fig. 4, Slip Joint Spline Wear Checking

  7. Visually examine the driveshaft tubes for dents, bends, twists, or other damage. If any tube appears to be damaged, have it repaired or replaced by an authorized Western Star dealer.
  8. Examine the driveshaft for evidence of missing balance weights, and for build-up of foreign material. Remove any foreign material. If there is any evidence that balance weights are missing, have the driveshaft removed and balanced.
  9. For driveshafts with slip joints, check to be sure the yoke plug is not loose or missing. See Fig. item 2. Have your Western Star dealer repair or replace the yoke plug as needed. If the yoke plug is missing, the splined shaft may be hitting the plug and knocking it out; have your Western Star dealer determine the correct driveshaft length.

    • After grease appears, cover the pressure-relief hole while continuing to lubricate.

    1. Slip Joint Grease Fitting (with grease gun attached)

    2. Yoke Plug

    3. Grease

    4. Half-Round Yoke

    5. Yoke Plug Pressure-Relief Hole

    6. Slip Joint Seal

    7. Full-Round Yoke

    8. U-Joint Grease Fitting

    Fig. 5, Slip Joint and U-Joint Lubrication

Note:
Parent topic: Driveline
Document Number: 0000120997
Manual Publication Date: 2024-05-23
Topic Publication Date: 2024-10-31