Service Home 40T - Gearbox - Troubleshooting Guide - NGC

40T - Gearbox - Troubleshooting Guide - NGC

11.2 40T - Gearbox Troubleshooting

Last updated: 10/12/2022

40T - Gearbox - Troubleshooting Guide - NGC

Introduction

Download and fillout the Gearbox Inspection Report Checklist below before replacing any parts.

Gearbox Inspection Report Checklist

40 Taper Gearbox Lubrication System

Gearbox Assembly Diagram

40-taper Gearbox

  1. Gearbox oil pump
  2. High gear shifter oil tube
  3. Spindle drive belts
  4. High/low gear proximity sensors or mechanical switches

Exploded View 40T

  1. SPINDLE MOTOR 10HP LINCOLN
  2. GEAR 16DP 40 TOOTH 2.05"
  3. FITG JIC-5-F X -5 HOSE STR
  4. RETAINING RING 1.875 INT BASIC
  5. SHCS 5/16-18 X 1
  6. GEARBOX TOP PLATE 16DP-65T
  7. HHB 1/2-13 X 1 3/4 GRADE 8 PLAIN
  8. SPRING BELVIL 1.206ID X 1.831OD X 0.059
  9. BEARING M17-47-14 OIL
  10. GEARBOX TRANSFER GEAR ASSY 16DP65T
  11. NUT 7/16-20, LOCKING
  12. SHIFT FORK 40T GEARBOX
  13. BEARING M25-47-12
  14. RETAINING RING 1.000 EXT BASIC
  15. RETAINING RING 0.669 EXT BASIC
  16. HOUSING GEARBOX MACHINED
  17. FITG HOSE BARB3/8 NPT1/4M 90 BRASS
  18. SHCS 10-32 X 7/8
  19. SPROCKET
  20. SHIFTER SHAFT
  21. QUAD-RING Q4-114 VITON NOT FOR SALE
  22. SHIFTER BODY
  23. SHCS 10-32 X 2
  24. 40T SWITCH MOUNTING BRACKET
  25. PICK UP TUBE DRY SUMP
  26. SHCS 1/4-20 X 1/2 ZINC
  27. SHCS 10-32 X 3/8 W/ FLAT WASHER OD 0.37-
  28. NIPPLE 1/2 NPT X 4 1/2 BRASS
  29. FITG HOSE BARB1/4 NPT1/4M STR BRASS
  30. FITG PC1/4F NPT1/8M 90 STL
  31. ENCODER SPRING MOUNT
  32. S SEAL 26MM ID X 52MM OD X 8MM
  33. RETAINING RING 2.047 INT BASIC
  34. SHCS 10-32 X 1 1/4
  35. GEARBOX GEAR LUBE MANIFLOD 16DP-40T
  36. GEARBOX GEAR LUBE MANIFLOD CONN TUBE
  37. GEARBOX GEAR LUBE MANIFLOD 16DP-32T
  38. SPRING BELVIL 1.403ID X 2.028OD X 0.059
  39. BEARING M25-52-15 OIL
  40. GEARBOX DRIVE GEAR ASSY 16DP65T
  41. BEARING M30-72-19 OIL
  42. F SEAL 1.125 X 1.595 X 0.240 F
  43. VIBRATION ISOLATOR UPPER
  44. SPACER
  45. VIBRATION ISOLATOR LOWER
  46. OIL CATCH PAN
  47. HIGH GEAR TUBE 40T GEARBOX-Co R0.438"
  48. PROXIMITY SENSOR
  49. DRAIN TUBE DRY SUMP
  50. F SEAL 0.875 X 1.345 X 0.350 F
  51. SUMP BRACKET
  52. SUMP TANK

Symptom Table

Symptom Possible Cause Corrective Action

Alarm 4.126 GEARBOX FAULT

 Insufficient air volume. Make sure that air supply meets the requirements, and check for leaks.
The high or low gear status sensor is faulty. Troubleshoot the sensors.
The high or low gear solenoid is faulty. Troubleshoot the solenoid.
Damaged gearbox. Make sure the gearbox shifts when applying air to it.
Shift dampener installed. Remove the shift dampener.
Alarm 4.126 GEARBOX FAULT intermittently generated on machines built with a digital SMC gearbox solenoid There is a small delay when the solenoid is commanded, thus causing the alarm to generate. Order service kits 93-3450 & 93-3452 and follow the Low Load Solenoid Valve Kit - Installation procedure.
Alarm 4.2011 LOW GEARBOX OIL LEVEL The oil level is low. Fix the leaks and refill with oil.
The NGC software is outdated.
 Starting in NGC software version 100.17.000.2045 to 100.19.000.1003 the control only monitors the gearbox oil level condition at power-on. Once the gearbox low oil condition is detected, the icon will clear on the next power on when a normal level condition is detected.  If you are getting a Low Gearbox Oil icon during machine operation, make sure you update the software to 100.17.000.2045 or higher.  Too much oil will cause a leak,  drain the oil and fill with the correct amount.

Note:  In software version 100.19.000.1102 and higher the gearbox oil level is checked continuously when the spindle fan is off.  After the spindle fan turns off, there is a delay before gearbox oil level monitoring begins.  Press the [RESET] to clear the low gearbox oil icon.
Oil level switch is faulty. Troubleshoot the oil level switch.
Orifices getting clogged causing a leak. Blow air through the orifices to unclog, 
Sump tank missing weep hole and a change to foam gasket.  Drill the weep hole on the backside (encoder side) of the sump tank. Clean thoroughly after drilling to not introduce debris.
Alarm 4.2012 LOW GEARBOX OIL FLOW The oil level is low. Fix the leaks and refill with oil.
There is a clog in the oil-pump inlet screen. Clean the inlet screen.
There is a problem with the oil flow switch. Troubleshoot the oil flow switch.
The oil-pump motor does not receive power. Troubleshoot the oil-pump motor.
There is a problem with the oil-pump motor gears or coupler. Inspect the gears or coupler.
Faulty P-Tech oil pump If the machine was manufactured before August of 2019 and the gearbox oil pump is a P-Tech P/N TTM-0669, replace the oil pump.  Note:  Do not replace the P-Tech pump if the P/N does not match the one mentioned above.
Orifices getting clogged causing a leak. Blow air through the orifices to unclog, 
On a machine with a NGC control:  A Low Gearbox Oil icon appears during machine operation. The NGC software is outdated. Starting in NGC software version 100.17.000.2045 to 100.19.000.1003 the control only monitors the gearbox oil level condition at power-on. Once the gearbox low oil condition is detected, the icon will clear on the next power on when a normal level condition is detected.  If you are getting a Low Gearbox Oil icon during machine operation, make sure you update the software to 100.17.000.2045 or higher.  Too much oil will cause a leak,  drain the oil and fill with the correct amount.

Note:  In software version 100.19.000.1102 and higher the gearbox oil level is checked continuously when the spindle fan is off.  After the spindle fan turns off, there is a delay before gearbox oil level monitoring begins.  Press the [RESET] to clear the low gearbox oil icon.
Sump tank missing weep hole and a change to foam gasket.  Drill the weep hole on the backside (encoder side) of the sump tank. Clean thoroughly after drilling to not introduce debris.
Noisy Gearbox  The oil level is low.
Fix the leaks and refill with oil. Fix the leaks and refill with oil.
The drive belts are worn or incorrectly adjusted. Set the belt tension.
The encoder feedback is faulty. See the Excessive Gearbox Noise section below.
Damaged or worn out encoder pulley or encoder belt. Inspect the encoder pulley.
Run-out or play within the encoder. Check for runout or play.
The gears are damaged. Perform a vibration analysis.
Noisy Gearbox after a Gearbox replacement. The gearbox may need to be broken in. Write a program to run the gearbox on high at 50% max RPM for 2 hours and then to run the gearbox on low at 50% max RPM for another 2 hours.
High Load Bad connection at the Wye/Delta contactor. Troubleshoot Wye/Delta assembly.
Oil leaking from output shaft. Sump tank missing weep hole and a change to foam gasket.  Drill the weep hole on the backside (encoder side) of the sump tank. Clean thoroughly after drilling to not introduce debris.
Spindle motor temperature sensor fluctuating  Electrical noise around that area. Refer to: Analog Sensors - Troubleshooting Guide - NGC 

Drive Belts

Corrective Action:

Check for damage to the pulleys. Check the drive belts for wear and correct tension.

High/Low Gear Sensors

Corrective Action:

Check for contamination of the connectors. Reseat the connections.

Make sure the sensor is tight on the bracket and gearbox. Image shows a 50T [1] and 40T [2].

Refer to the Proximity Sensor - Troubleshooting Guide.

High/Low Gear Solenoid

Corrective Action:

Use a voltmeter to check for 120 VAC at the solenoid.

The solenoid may be located on the 50T gearbox [1], the 40T gearbox [2] or in the CALM cabinet [3].

Refer to the Solenoid - Troubleshooting Guide.

Oil Pump Gears/Coupler

Corrective Action: Inspect the gears or coupler.

Remove the top assembly [1] of the oil pump. Inspect the gears [2]. Make sure they are in good condition. Inspect the sleeved coupler [3]. Replace the sleeved coupler (P/N 93-30-5725) if it is broken.

Low Ambient Shop Temperature

Corrective Action:

Warm up the machine by running the spindle at high speed for 10 minutes to warm up the gearbox housing and the oil.

Oil Flow Switch

Proximity Senor Oil Flow Switch:
  1. Fittings
  2. Retention clip
  3. Steel ball
  4. Oil flow sensor housing
  5. Proximity sensor

Corrective Action:

Remove the oil flow sensor from the oil-pump assembly. Use a screw driver to manually operate the switch. Navigate to the I/O tab in DIAGNOSTICS. Make sure the diagnostic bit for Low Lube Press. changes from 0 to 1.

 Note: The name of this diagnostic bit in older software versions is Low GB Oil Flow.

Check Valve Style Oil Flow Sensor:

Corrective Action 1:

Unplug the oil flow sensor and remove it from the oil-pump assembly. Use a screw driver to manually depress the sensor plunger.  Use a multi meter to monitor continuity across the switch leads.  If continuity is made when the plunger is depressed and broken when the plunger is released the sensor is working properly.

If the sensor is not working properly loosen the two phillips head screws that attach the sensor to the fitting.  Adjust the sensor position until actuating  the plunger reliably makes continuity when the plunger is depressed and breaks continuity when the plunger is released.

Corrective Action 2:

Plug the oil flow sensor in and monitor the diagnostic bit for Low Lube Press. as you manually actuate the sensor.

If the diagnostic bit for Low Lube Press. does not change from 0 to 1, disconnect the oil flow sensor from the connector bracket. Put an electrical jumper across the (2) pins in the connector for the oil flow sensor [1]. Make sure the diagnostic bit for Low Lube Press. changes from 0 to 1. If the input changes, the oil flow proximity sensor is faulty.

If the diagnostic bit for Low Lube Press. does not change from 0 to 1, disconnect the cable from the P12 connector [2] on the I/O PCB. Put an electrical jumper across pins 2 and 3 of the P12 connector. Make sure the diagnostic bit for Low Lube Press. changes from 0 to 1. If the input changes, the 950 cable is defective. If the input does not change, troubleshoot the I/O PCB.

Corrective Action 3:

The oil flow sensor (32-2323) should be replaced before swapping the gearbox or replacing parts. The spring in the switch might be too stiff to actuate the switch even though there is sufficient oil flow to the gearbox. 

HSG-N 04/04/2024

Oil Pressure Switch

Corrective Action:

Make sure the pressure switch connection is clean and well seated.

Use a voltmeter to check the continuity of the pressure switch when the pump is running. If the switch is open (O.L.) when there is pressure in the system, replace it.

Check the pressure switch with a voltmeter when the pump is running. If the switch is open (O.L.) when there is pressure in the system, replace it.

Oil Level Switch

Corrective Action:

Remove the oil-level switch from the gearbox. While you move the float from position [2] to position [1], measure for continuity across pins 2 and 4 of the connector for the oil-level switch.The oil-level switch operates correctly when:

  • There is not continuity when the magnet is at position [2].
  • There is continuity when the magnet is at position [1].

Replace the oil-level switch if it does not operate correctly.

Disconnect the 950 cable from the P12 connector on the I/O PCB. Measure for continuity across pins 1 and 3 of the connector for the oil-level switch on the 950 cable. If there is continuity, there is a short circuit in the 950 cable. Replace the cable.

Put an electrical jumper across pins 1 and 3 of the P12 connector. Press [PARAM/DGNOS] twice. Navigate to the I/O tab. Make sure the diagnostic bit for Low GB Oil Level changes from 1 to 0. If the input does not change, troubleshoot the I/O PCB.

Oil Filter

Corrective Action:

Put a wrench [2] on the straight male-fitting [1] to make sure it does not move. With another wrench [3], turn the hose and the barbed fitting [4] counterclockwise to remove them.

Put a wrench [6] on the inlet-screen housing [5] to make sure it does not move. With another wrench [7], turn the straight male-fitting [8] counterclockwise to remove it.

Remove the spring [1] and the inlet screen [2] from the inlet-screen housing [3]. Clean the inlet screen [4]. Reinstall the inlet screen.

Oil-Pump Motor

Corrective Action: Troubleshoot the oil-pump motor.

Command the spindle to operate.

 Note: There is a voltage output to the gearbox oil pump when the spindle operates.

Monitor the motor fan on the gearbox oil pump. If the motor fan on the gearbox oil pump does not operate, make sure the oil pump receives the correct voltage. Use a multimeter with needle-tip probes to measure the voltage across the cable connector for the gearbox oil pump.

 Note: Do not measure the voltage with the oil pump cable disconnected from the 300A cable.

The measured voltage must be 120 VAC. If the voltage is correct and the pump does not operate, go to Section 6.

If the voltage is not correct, make sure the voltage output from the I/O PCB is correct. Use a multimeter with needle tip test probes to measure the voltage between pin 1 and pin 2 on the 300A-cable connector at P41 (Classic Haas Control) or P32 (Next Generation Control) on the I/O PCB.

 Note: Do not measure the voltage with the 300A cable disconnected from the P41 connector on the I/O PCB.

The measured voltage must be 120 VAC. If the measured voltage is correct, the 300A cable is defective. If there is no voltage output, refer to these troubleshooting guides:

Sump Tank Missing Weep Hole

Cause:

Sump tank missing weep hole and a change to foam gasket. 

Corrective Action:

Drill the weep hole on the backside (encoder side) of the sump tank.

1. ø.094 THRU ONE WALL 0.20” From Top Of The Tank.

Clean thoroughly after drilling to not introduce debris.

Note: Do not drill a hole on the front side (spindle side) as coolant can enter the sump.

Wye/Delta Contactor

A worn contactor can send unreliable power to the gearbox motor, which can cause a high load. Check the connections at the Wye/Delta contactor. Make sure the terminals are tight.

Corrective Action:

Refer to Wye-Delta Contactor - Troubleshooting Guide to troubleshoot the Wye/Delta connectors.

Excessive Gearbox Noise

Corrective Action:

Determine if the problem is mechanical or electrical by commanding the spindle rpm where the noise is heard and then turning off the power.

If the noise goes away this means that the cause of the noise may be the encoder feedback.   

Damaged gears in the gearbox can cause excessive noise. Contact your local HFO for a vibration analysis to see if the gears are damaged.

Gearbox

Corrective Action:

Manually actuate the High/Low gear solenoid and slowly turn the spindle by hand. The gearbox should shift and the Hi Gear and Low Gear bits on the diagnostic page should change state.

If the gearbox does not shift, it may have internal damage.

If the gearbox shifts, refer to these troubleshooting guides for the high and low gear solenoids and the I/O PCB.