TM 5-3805-258-24-1P O W E R T R A I NT R A N S M I S S I O N N E U T R A L I Z E R G R O UPS Y S T E M S O P E R A T I O NIf the transmission is engaged in either FOR-WARD or REVERSE, levers (4) will come in con-tact with cam (7). The force of spring (8) causes cam(7) to move when contact is made with the levers.Since cam (7) is connected to the direction selectionspool by rod (5), the direction selection spool will alsomove. The direction selection spool is moved from theFORWARD or REVERSE position, to the NEU-TRAL position.With the transmission in NEUTRAL, switches (10)and (11) are in the positions shown. See Illustration A.I L L U S T R A T I O N A(Engine Running, Transmission in Neutral,Parking Brake Not Engaged)10. Switch. 11. Switch. 12. Back-up alarm. 13. Masterfaultlight. 14. Parking brakepressureswitch. 15. Faultalarm.Switch (10) is part of the back-up alarm system.Switch (11) is part of the parking brake warningand alarm system.When a shift is made to either FORWARD orREVERSE, cam (7) moves to the left or right. Themovement of cam (7) causes switch (11) to be in thepositions shown in ILLUSTRATIONS B and C.When the parking brake is engaged, air pressure isstopped to parking brake pressure switch (14). Whenthe air pressure goes below approximately 450 kPa(65 psi), switch (14) opens and parking brake indica-tor (13) goes “ON”. Indicator (13) is on the EMS(Electronic Monitoring System) panel.With the parking brake engaged, pressure alsodecreases at the transmission neutralizer group. Theneutralizer group moves the transmission selectorlever to the NEUTRAL position.The transmission selector lever can be held in theFORWARD or REVERSE position, while theparking brake is engaged. At this time however,the master fault light (13) (to the right of the oper-ator’s seat) will come “ON” and fault alarm (15)will sound.I L L U S T R A T I O N B(Engine Running, Transmission in Forward,Parking Brake Engaged)10. Switch. 11. Switch. 12. Back-up alarm. 13. Masterfault light. 14. Parking brakepressure switch. 15. Faultalarm.When the transmission lever is released, the leverwill return to the NEUTRAL position. At this time,the fault alarm and the master fault light will go“OFF.”Therefore, before a full warning is given, theparking brake must be engaged and the transmis-sion in either FORWARD or REVERSE.When a shift is made to the REVERSE position,cam (7) moves to the left. The movement of cam (7)causes switch (10) to be in the position shown inIllustration C. Switch (10) is part of the back-upalarm system. At this time, switch (10) closes andthe back-up alarm will sound.When a shift is made to either NEUTRAL orFORWARD, switch (10) opens and the back-upalarm will not sound.I L L U S T R A T I O N C(Engine Running, Transmission in Reverse,Parking BrakeEngaged)10. Switch. 11. Switch. 12. Back-up alarm. 13. Masterfaultlight. 14. Parking brakepressure switch. 15. Fault3-50alarm.
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