TM 10-3930-669-34 2-12.  DRIVE AXLE TROUBLESHOOTING (CONT.). 4.  DRIVE AXLE ENGAGING HARSHLY WHEN SWITCHING DIRECTION. INITIAL SETUP Tools and Special Tools References Tool Kit, General Mechanic’s: Automotive TM 10-3930-669-10 (Item 1.  Appendix E) Equipment Condition Drive axle removed (Para 10-2) KNOWN INFO Nothing. POSSIBLE PROBLEMS Differential case pins faulty. Differential case and / or side gear washers faulty. TEST OPTIONS Visual Inspection. REASON FOR QUESTION If differential case pins are faulty, drive axle will engage harshly when switching direction. 2-84 (Para 10-2).