DTC:

Bulletin:

P1075-75

GDC17-016

Date:
Description:
Applies To:

December 18, 2020

Clutch System - Emergency position not reachable
US13 – US20 Emissions

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General Information
These repair instructions are intended to address the following fault(s):
DTC

P1075 - 75

Description
Clutch System Emergency
position not
reachable

Possible (Observable)
Symptoms

Possible Cause
•
•
•

Air leakage, Clutch system
Clutch cylinder
Clutch valve assembly

Starting gear D/Rev
does not engage
Engine Shut Down

•
•

Required Parts
Part Number

Description

Quantity

22440568

Clutch Cylinder Assembly

1

Repair Instructions
Clutch Cylinder, Replacement

Note: Do not attempt to repair or service this vehicle without having sufficient training, the correct service literature
and the proper tools. Failure to follow this could make the vehicle unsafe and lead to serious personal injury or
death.
Note: Before beginning any work on any part of the air system, be certain that the air pressure has been released.
Failure to do so may cause a component to violently separate, which can result in serious personal injury.
1.
2.
3.
4.

Apply the parking brake.
Disconnect power to the vehicle by removing the batteries negative cable.
Drain the air system.
Raise the vehicle and support with jack stands.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 1/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

5. Disconnect the transmission oil cooler hoses from the filter housing. Special tools: 85108826

6. Remove the drive shaft. Note: Remove the universal joint caps and the bolts holding the intermediate bearing
to the support bracket (if equipped). Note: Mark the position of the bolts on the bracket so that the
intermediate bearing is installed in exactly the same position as before. Position the shaft aside.

7. Disconnect the air supply hose at the rear of the transmission.

8. Remove the tie straps securing the wiring harness to the transmission.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 2/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

9. Disconnect the electrical harness at the control housing, speed sensor, and the two chassis connectors. Note:
Position the harness out of the way.

10. Remove the cab engine cover.
11. Remove the transmission-to-engine mounting bolts along the bottom and sides of the clutch housing. Note:
Do not remove the top four transmission-to-engine mounting bolts at this time.
12. Position the transmission jack and secure the transmission to it.
13. Remove the bolts securing the battery cables to the brackets on the top of the clutch housing.
14. Remove the top four transmission-to-engine mounting bolts.
15. Carefully pull the transmission back until the input shaft clears the pressure plate. Lower the transmission and
pull it out from under the vehicle. Note: While lowering the transmission, periodically check around it to assure
nothing is caught or hung up on it such as wiring or air hoses.
16. Remove the service plug located on top of the clutch valve to ensure that no air remains in the system. Note:
The Clutch Valve Unit contains air under high pressure. Do not remove the drain plug entirely because doing
so may allow the plug to quickly and forcefully become a projectile. Leave the drain plug slightly cracked to
allow air pressure to be released. Failure to do so may result in serious personal injury.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 3/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

17. Carefully remove the tie straps for the wiring harness, and the air hose to the clutch cylinder.

18. Remove the clutch valve mounting bolts.

19. Disconnect the clutch position sensor wiring and position the clutch valve aside.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 4/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

20. Remove the clip holding the air hose in the clutch cylinder. Disconnect the air hose from the clutch cylinder.
Remove the clutch cylinder mounting bolts and then the clutch cylinder.

21. Clean and inspect the hose connections. Replace the hose O-rings. If there is any damage to the hose or
connections, replace the damaged part.
22. Remove the three fasteners and then the air hose fitting. Position the fitting on the new cylinder. Install and
torque the fasteners. Note: Replace the O-rings on the fitting. Specifications: 3±0.4 Nm (2±0.5 ft-lb)

23. Position the new clutch cylinder. Install and torque the mounting bolts. Specifications: 45±5 Nm (33±4 ft-lb)
24. Connect the air hose to the clutch cylinder and install the locking clip.

25. Check that the sealing surface on the clutch valve assembly is clean.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 5/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

26. Remove the screw retaining the cover plate on the back of the clutch valve.

27. Remove the rubber seal and then the filter. Note: Note the orientation of the gasket and the filter prior to
removal.

28. Install a new filter and then a new rubber seal. Note: The filter should be installed with the ridge facing
outward away from the valve.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 6/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

29. Install the cover plate on the back of the clutch valve using a new screw.

30. Connect the clutch position sensor wiring to the clutch valve.

31. Install and torque the clutch valve mounting bolts. Specifications: 20±3 Nm (15±2 ft-lb)

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 7/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

32. Secure the wiring harness and air hose in position with new tie straps.

33. To aid transmission installation, remove the service plug on the clutch control valve assembly and push the
piston all the way into the clutch cylinder. While holding the piston in, install the plug and torque.
Specifications: 7±2 Nm (5±1 ft-lb) Note: Failure to perform this step will hamper installation. The transmission
will be installed under clutch cylinder spring pressure and will fail to freely slide forward into place against the
engine mating surface.

34. Carefully install the transmission and align it to the engine. Loosely install two upper and two lower
transmission-to-engine mounting bolts to hold the transmission in place. Note: The use of an assistant may be
necessary to aid installation. Note: Rotate the input shaft to align the clutch splines.
35. Install the remaining transmission-to-engine mounting bolts, torque the bolts and remove the transmission
jack. Note: To aid access, install and tighten the mounting bolts on the top of the clutch housing first. Remove
the transmission jack and install the remaining mounting bolts. Specifications: 92±8 Nm (68±6 ft-lb)
36. Position the battery cables and install their mounting bolts.
37. Install the cab engine cover.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 8/10

DTC:

P1075-75

Bulletin:
Date:

GDC17-016
December 18, 2020

38. Position the electrical harness and reconnect the control housing, speed sensor, and the two chassis
connectors.

39. Install new tie straps to securing the wiring harness to the transmission.
40. Connect the air supply hose at the rear of the transmission.

41. Connect the transmission oil cooler hoses to the filter housing.

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 9/10

DTC:

Bulletin:

P1075-75

Date:

GDC17-016
December 18, 2020

42. Install the drive shaft, the universal joint caps and the bolts holding the intermediate bearing to the support
bracket (if equipped). Note: Install the universal joint caps and the bolts holding the intermediate bearing to
the support bracket (if equipped). Note: It is important to center the rubber insulator in the U-bracket correctly.
Specifications: Intermediate Bearing – 175±30 Nm (129±22 ft-lb) Universal Joint Caps – 166±10 Nm (122±7
ft-lb)

43.
44.
45.
46.

Remove the supporting jack stands and lower the vehicle.
Pressurize the air system and check for leaks.
Restore power to the vehicle by connecting the batteries negative cable.
Check and fill the transmission with approved transmission oil.

47. After the transmission is installed, it is necessary to perform a clutch engagement point calibration using the
scan tool.
Additional Resources
These repairs are the most likely fix for the identified fault, if this does not fix the issue, Tech Tool will need to be
used for more detailed diagnostics. If filing a warranty claim, please include the ASIST case number.
Labor Code
4134-03-02-05

2.9 - 4.2 (May vary depending on year/model)

Causal Part

22440568

© 2020 Mack Trucks, Inc. Information is subject to change without notice.

Page 10/10

DTC:

Boletín:

P1075 - 75

Fecha:
Descripción: