Driveline troubleshooting

A number of problems can be associated with poor driveline performance, below we offer information on how to identify the problem and additional information on what may be causing the condition to help you in diagnosing the problem:

1. Vibration
2. Premature Wear
3. Slip Spline Wear
4. Shaft and/or Tube Failure
5. Yoke Failure

PROBLEM -- Vibration

• Low gear shudder
• At certain speeds under full drive or full coast
• Under light loaded conditions

Causes

Solutions

Secondary couple load reaction at shaft support bearing Improper phasing Incompatible driveshaft Driveshaft weight not compatible with engine-transmission mounting Driveshaft too long for speed Loose outside diameter fit on slip spline Excessively loose u-joint for speed Driveshaft out of balance; not straight Unequal u-joint angles U-joint angle too large for continuous running Worn u-joint Inadequate Torque on bearing plate cap screws Torsional and/or inertial excitation

Reduce u-joint continuous running angle Replace u-joint Install two-piece driveshaft with shaft support bearing Use large diameter tube Shim drivetrain components to equalize u-joint angles Straighten and balance shaft Check with transmission or axle manufacture -drive shaft repair Inspect u-joint flex effort for looseness - torque to specification Check driveshaft for correct yoke phase

   PROBLEM -- Premature Wear

Low mileage u-joint wear Repeat u-joint wear End galling of the cross trunnion and bearing assembly Needle rollers brinelled into bearing cup and cross trunnion Broken cross and bearing assemblies    Broken Cross Causes Solutions End yoke cross-hole misalignment Excessive angularity Improper lubrication Excessive continuous running load Continuous operation at a high angle/high speed Contamination and abrasion Worn or damaged seals Excessive torque load (shock loading) for u-joint and driveshaft size Use special alignment bar to check for end yoke cross-hole misalignment, replace end yoke if misaligned Check u-joint operating angles with a spirit level protractor or Spicer Anglemaster®II, reduce excessive u-joint operating angles Lubricate according to specifications Replace u-joint kit Reduce u-joint continuous running angle Replace with higher capacity u-joint and driveshaft Check u-joint flex effort -- replace joint or yoke if necessary Clean and re-lubricate u-joint Realign to proper running angle -- minimum 1/2 degree Torque bearing retention method to specification  PROBLEM -- Slip Spline Wear Seizure Galling Outside diameter wear at extremities and at 180 degrees Spline shaft or tube broken in torsion  Causes Solutions Improper lubrication Worn or damaged part Tube size inadequate Excessive torque load for u-joints and driveshaft size Male spline head engagement length too short for application Excessive loose outside diameter fit Slip member working in extreme extended or fully collapsed position Contamination Lubricate slip spline according to specifications Replace with higher capacity u-joint and driveshaft Check u-joint flex effort -- replace joint or yoke if necessary Clean and re lubricate according to specification Replace spline -- check design for the application Use Spicer Glidecote slip spline Increase driveshaft assembly length to position slip spline head towards u-joint Check for male slip member with longer spline Use larger diameter tube PROBLEM -- Shaft and/or Tube Failure  Shaft support bearing wear or fracture Shaft support rubber insulator wear or fracture Tube circle weld fracture Causes Solutions Balance weight located in apex of weld yoke lug area Balance weight too close to circle weld Improper circle weld Bending fatigue due to secondary couple loads Driveshaft too long for operating speeds Worn or damaged parts Excessive torque load (shock loading) for u-joint, double cardan joint and driveshaft size Improper lubrication of bearings Shaft support bearing misaligned -- interferes with slinger Reduce u-joint continuous running angle Replace with higher capacity u-joint and driveshaft Install two-piece driveshaft with shaft support bearing Use larger diameter tube Normal bearing wear -- replace Realign mounting bracket to frame cross member to eliminate interference with slinger PROBLEM -- Yoke Failure Yoke broken in hub Yoke broken at ear tip Causes Solutions Mating yoke lug interference at full jounce and rebound Excessive torque load for u-joint and driveshaft size Improper shaft length and slip Bending fatigue due to secondary couple loads Reduce u-joint continuous running angles Replace with higher capacity u-joint and driveshaft Replace yoke -- check design for application Use wide-angle yokes Check installed lengths and adjust driveshaft length to provide proper slip conditions. Read more article to click here-

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