03/24/07 TRANSMISSION Transmission won t engage into Gear This is caused usually by too low a Voltage to get into the ECM. This unit requires a minimum of 9VDC in order to operate at all. Almost all erratic Transmission behavior can be traced to insufficient Voltage into the ECM. The Maintenance Manual has several pages for trouble shooting various components, but it would take a Transmission shop to perform these tests since it is hard to reach and or do the correct readings and connections. A PR-61 Tester is the tool for all problem solving, but its not available to the oprator. For a quick initial check try: Recycling the switches and shutting the entire coach off and back on. (This is also on Chptr.9 pg. 35) If this fails to engage a gear, the following systematic check may have to be used: 1. Check on Throttle sensor It has to line up on IDLE - LOW/ FULL HIGH and the linkage should be tight. 2. Two feet from the sensor is a 1 Plug which is a bypass sensor. Unplug this and see if a rough gear engagement takes place. 3. Open the shift Panel (left front console) and check for open ground between #15 (blue) and #24 (brown) wires Ignition ON: In Drive (no engine running) OPEN Ground In Neutral - CLOSED Ground 4. Check the fuse on the circuit board in the ECM (behind carpet wall left of steering wheel). Only 1 angled in screw holds this piece in place. If this fuse is blown, a 10 Amp Fuse could be used to replace it but it is for Emergency run only, NOT a permanent fix. 5. Disassemble the harness to the top of the ECM and expose the 35 wires Check for Voltage to transmission by IGNITION ON select D (no engine) 12 Volt DC between #18 (white with black stripe wire) and #24 (brown, Grd.) Between #5 (white with yellow stripe) and #24 My test stopped here since the coach would suddenly engage a gear. *(I was riding on luck for 3 years, since did a bad wiring job.) NOTE For a more detailed list of Transmission problems, causes, checks and remedies, see the next several pages and Chapter 9 pages 31-35. Above procedure was encountered on several occasions, got the coach running again, but never fixed the root of the problem. Page 1
03/24/07 The following items are listed here for a easier reference in case of a transmission problem which was encountered on several occasions TROUBLESHOOTING GUIDE 1. Engine cannot be started 2 Lockup clutch does not engage 3. Lockup clutch does not disengage 4. Transmission does not upshift 5. Transmission does not downshift 6. Reverse gear does not engage 7. Incorrect shift points 8. Shift Points too hard 9. Engine races during shifting 10. Retarder not functioning 11. Retarder does not cut out 12. Excessive Retarder effect 13. Retarder response time too long (responds too slowly) 14. Oil temperature too high 15. Oil loss, excessive oil consumption 16. Not enough traction 17. Transmission does not engage 18. Transmission engaged when shift selector is in neutral NOTE: The items in this troubleshooting guide are arranged in sequence, with the easiest checks and remedies listed first. Less frequent faults and time-consuming remedies are listed last. Page 2
03/24/07 Engine cannot be: started Transmission shift selector not in neutral position Transmission electrical system not correctly connected up Check plugs at shift selector and control Fuse of; transmission electrical system blown Starter lockout defective Test output signal with PR-61 tester Move shift selector to neutral Position correctly Renew fuse Renew relay Renew control unit Lockup clutch does not engage - Inductive sensor (turbine) defective Check internal resistance Renew inductive sensor - Inductive (turbine) sensor incorrectly set Check clearance Converter defective Renew converter - Hydraulics defective Renew complete hydraulic system - Test signal output with PR-61 tester Lockup clutch does not disengage - Incorrect inductive (turbine) sensor setting - Inductive sensor defective Check internal resistance Renew Inductive Sensor - Test output signal with PR-61 tester - Hydraulics defective Renew complete control box Transmission does not upshift Converter defective - Inductive sensor on output incorrectly set Inductive sensor or connection defective Check internal resistance Solenoid valve defective Test internal resistance with test cable Hydraulics defective Simulate upshift with PR-61 tester Transmission does not downshift Incorrect inductive sensor setting on output Inductive sensor defective Test internal resistance with test cable Simulate downshift with PR-61 tester Renew converter Renew inductive sensor or renew/repair wiring Renew complete control box Renew inductive sensor and readjust Page 3
03/24/07 Reverse gear does not engage Solenoid valve defective Test with test cable Hydraulics defective Test clutch indicator with PR-61 tester Generated by Foxit PDF Creator Foxit Software Renew valve body Incorrect shift points Incorrect load sensor adjustment Check adjustment Load Sensor defective Test Voltage with PR-61 tester Inductive sensor incorrectly set on output Test with PR-61 Hard Shifts Incorrect load sensor adjustment Check adjustment Hydraulics defective Adjust Linkage Renew load sensor Renew Control Box Renew linkage Renew complete control box Engine races during shifting Check Oil level Solenoid Valve defective Oil Filter blocked Main Pressure too low Measure main pressure at measuring point Adjust Oil level Renew complete solenoid valve Renew oil filter, change oil, consult ZF Retarder not functioning Check Oil level Retarder switch off No voltage in Retarder solenoid valve Test electrical system with PR-61 Loose electrical connection Brake pressure switch defective Test with PR-61 tester or voltmeter No air at Retarder solenoid valve Check air pressure at solenoid valve Retarder solenoid valve defective Unscrew solenoid valve, check air passage Retarder control valve not operating Check pressure R3 at measuring point 5 Test with PR-61 tester Transmission damaged Switch on Retarder Correct electrical fault Check and tighten plugs Renew switch Check compressed air supply Renew Retarder solenoid valve Renew transmission Page 4
03/24/07 Retarder does not cut out Retarder solenoid valve defective Unscrew solenoid valve, check air passage Brake pressure switch defective Test with PR-61 tester or voltmeter Test Retarder output with PR_61 tester Generated by Foxit PDF Creator Foxit Software Renew switch Retarder effort too low Air pressure at Retarder control valve tool low Check air pressure at control valve Retarder control valve defective Check pressure R3 at measuring point 5 Retarder response time too long (responds too slowly) Solenoid valve on accumulator defective Unscrew solenoid valve, check air passage No Voltage at accumulator solenoid valve Test electrical system with PR-61 tester No air at accumulator solenoid valve Unscrew compressed air supply to solenoid valve Check compressed air supply Oil Temperature too high Loose electrical connection Check and tighten Temperature sensor or temperature gauge defective Renew temperature sensor or Temperature gauge Oil level too high or too low Lockup clutch not engaging see previous (2) Coolant circuit faulty Check coolant circuit, check radiator Top up coolant, clean radiator Retarder does not cut out See previous (11) Transmission damaged Oil loss, excessive oil consumption Incorrect oil level Oil drain plug leaking Accumulator leaking Not enough traction Engine not reaching full speed or power Check governed speed and stall speed Converter damaged and stall speed Insert sealing ring Renew Accumulator Check accelerator and governed pressure linkage, consult ZF Page 5
03/24/07 Transmission does not engage Control Box in safety lockup mode Turn off ignition, restart engine Turn off ignition, restart engine Control Box de-energized, loose electrical connection, fuse blown Test electrical system with PR-61 tester Reconnect, renew control box Transmission shift selector defective Test with PR-61 tester Renew shift selector Test clutch indicator with PR-61 tester Solenoid valve defective Check solenoid valve function and internal resistance with test cable Oil filter blocked Check filter, consult ZF Renew oil filter Transmission locked Check oil filter, check oil level Transmission engaged when shift selector is in Neutral Shift selector is defective Test shift selector with PR-61 tester Renew shift selector Test clutch indicator with PR-61 tester Clutch seized, check oil filter Page 6