K25756018

Solution K25756018
Monday, November 4, 2019 9:28:18 PM CET
** SOLUTION **
Title
Vehicles With An Automated Manual Transmission (AMT) - Power Take-Off Diagnosis
And Repair; PTO Air Leaks, Oil Leaks, Engagement, Noise
Mack Models
AN - Anthem , CHU - Pinnacle, Axle back , CXU - Pinnacle, Axle front , GR - Granite
Mack Model
, GU - Granite , PI - Pinnacle , TD - Titan
Volvo Models
VN , VNL , VNM , VNR , VNX , VAH , VHD
Volvo Model
Emission Standard
Emission Standard
US07 , US10 , US10+OBD13 , US14+OBD13 , US14+OBD15 , US14+OBD16 , US
17+OBD16 , US17+OBD18 , US17+OBD19
Engine family
Engine family
11L Engine , 13L Engine , 16L Engine , MP7 , MP8 , MP10
Transmission
Transmission
AMT-F , AMT-F With Crawler Gears , AMT-F Without Crawler Gears , AMT-C , A
MT-D , AMT-F , AMT-C , AMT-D , AMT-F , AMT-F With Crawler Gears , AMTF Without Crawler Gears
** SOLUTION **
Cause
The service instructions for the gearbox mounted AMT PTO have not been readily
available to the NA market when the PTO was made available for the AMT in
NA. Although many of the parts have been available for the PTO in the NA parts
system, not all parts are available because major components like gears and housing can
quickly drive the cost of repair higher than the replacement cost. The parts that are
available in NA parts system represent a reasonable repair option when internal
inspection of the PTO and the failure mode show that a simple repair in the field is
possible. See the failure mode and repair option information below for more information.
Solution
Where to find repair instructions
Language settings must be returned to English (United States) after following the instructions
below. CBR will not function correctly if the language is improperly set in Impact.
Note: Not all dealers or users are set up to be able to do this.
Service instructions are available in Europe for all of the PTOs currently available in NA. Changes
are ongoing to make this information available in the NA market. Until that happens please use the
steps below to find the service instructions needed.
1. When looking for information in IMPACT click on the ‘Menu’ tab and select ‘My Settings’.
2. Change your preferred language to English (Great Britain) and hit ‘Save’
3. Under the service tab search for Model ‘FH (4)’ -- Select Function Group 48. Power Take-Off-All
service information and hit search.
3.1. Here you will find Design and Function and service documentation.
4. Select the PTO model you have from the list and then you can download or print the document for
reference.
Note: The PTO model is stamped in the case of the PTO.
Note: DO NOT forget to change language settings back when finished!
Fail modes
Note: This list assumes the PTO was previously working as designed and has stopped working properly and
is not limited to these descriptions.
Air leaking from gearbox vents when the PTO is engaged.
Air leaking from the vents with PTO engaged is an air seal issue. The seals are available, as are the gaskets
for the repair. The limiting factor is if the bore in the case that the piston is riding in is scored or worn.
1. Inspect the air piston for wear. Look for evidence of the piston making contact with the bore as shown
in the picture below.
- If wear is found, the bore needs to be inspected.
2. Inspect the piston bore. Check for any wear or damage as shown in the example below.
- If the bore is serviceable, the unit should be repaired. Replace the air piston and seals.
- If the bore is worn, replace the PTO. The piston bore is not repairable.
3. Check the piston and bore for rust.
- If Rust if found on the piston face, then there has been water intrusion to the piston. An example is
shown below.
Check the vehicle air system for moisture and correct the root cause of the water intrusion.
- If rust damage is found in the bottom of the piston bore, clean the bore and inspect the sealing surface
for damage. Rust in the bottom of the bore will not affect operation.
- If the vehicle air system is dry and properly serviced, the solenoid should be checked for a good rubber
cap on the top.
If the cap seal is damaged then replace the solenoid.
PTO solenoid electrical checks
The PTO solenoid contains two fly-back/clamping diodes to prevent high voltage reverse voltage spikes
from damaging the controlling ECU. Because of the orientation of these diodes, the unit will give
unexpected readings for resistance with a multi-meter.
When checking Resistance readings through the solenoid the following readings with a multimeter
should be observed:
- Resistance in the Mega OHM range when measured through normal polarity:
Positive lead to Pin 1, Negative lead to Pin 4.
- Open Circuit (OL) when measuring Resistance through reverse polarity:
Negative lead to Pin 1, Positive lead to Pin 4.
- Diode Check function: Test voltage value when measured with normal polarity:
Positive lead to Pin 1, Negative lead to Pin 4.
- Diode Check function: OL when measured with reverse polarity:
Negative lead to Pin 1, Positive lead to Pin 4.
- Power (12 V) and ground may be applied to the pins in normal polarity (12 V to Pin 1, Ground to
Pin 4) to check the solenoid function.
Applying power in reverse polarity will damage the
solenoid.
• Oil Leaks
All seals and gaskets are available in the parts system. Repair as needed.
- Leaking output flange seals or loose output flanges can be repaired on the truck without removing the
PTO from the gearbox if the unit does not need to be disassembled.
- Oil leaking from top of PTO solenoid will usually include air leaking from the gearbox vents when the
PTO is engaged. The air leaks section above should be reviewed.
NOTE: The customer may not notice the air leak if the PTO is working properly unless the leak is
large or they see an oil mist or ‘smoke’ coming from the vents.
• PTO Will Not Engage or Disengage, or Grinds During or After Engagement
If the PTO was functioning properly prior to the customer reporting this symptom, check to see that
the PTO ‘tries’ to engage when the switch is turned on.
1. With the switch turned on manipulate the wiring. See if the PTO engages or disengages due to an
electrical issue at the solenoids.
- AMT-C and AMT-D (2007-2016) PTO solenoids are controlled by wiring from the Transmission
Electronic Control Unit (TECU) and will log electrical faults when the wiring to the solenoids is
compromised.
- AMT-F (2017-Present) PTO solenoids are controlled by wiring from the Vehicle Electronic Control
Unit (VECU) and/or the Body Builder Module (BBM) and will not log electrical faults when the wiring
to the solenoids is compromised.
2. If the wiring is verified to be intact, the next likely item is a broken snap ring.
- The PTO drive shaft in the rear of the gearbox has a snap ring that contains the bearing to the shaft. If this
snap ring breaks the pieces may end up in the PTO and get lodged under the shift fork and bind the fork.
- Depending on where the piece gets stuck will depend on how the failure is described.
- If it is confirmed that the snap ring is the cause:
Repair as needed.
Disassemble and inspect the PTO for repair or replacement.
Examples of snap ring failure can be found below:
Pieces of ring get into the PTO and cause operational issues.
Spline and sliding clutch: Damaged components should be replaced
PTO case damage from snap ring or other debris can be cleaned up and
inspected. If the damage does not affect the operation of the PTO shifter and
piston seals the PTO can be repaired.
• Gearbox Low Lube, Mechanical or Contamination Failures
A gearbox that fails for a low lube condition does not necessarily mean that the PTO is failed
also. Contaminated oil may pass through the PTO, but may not necessarily cause damage. In several cases,
PTOs replaced with a gearbox failure that have been inspected have been deemed acceptable for reuse. The
PTO does not spin when not in use and so does not necessarily damage the internal parts due to low lube or
contamination seen in the oil. The smaller single PTOs get lube all the time but the larger double PTOs do
not. They only get oil from the gearbox when they are being used.
In cases of a gearbox failure of this nature, the PTO should be opened and inspected, cleaned, resealed
and reused if the PTO is not failed.
Except for the dark oil in the housing, this PTO was perfect even though the gearbox failed for low lube.
Acceptable repairs and available parts
For all the fail modes listed above the repairs are typically straight-forward.
• Seals and gaskets for all PTOs are available in the parts system.
• The available parts include but may not be limited to common fasteners (nuts, bolts, washers and
brackets), seals, gaskets, output flanges, sliding clutches and shift forks.
• Check parts availability for the repair.
• When the repair starts to involve the replacement of the PTO case, gears or bearings the cost of
parts and labor required to repair quickly exceeds the cost of replacement.
Standard Repair Times
Operation
Description
SRT
4811-03-02-02
PTO Replacement (Transmission), All Models
0.8 hr
4811-04-04-01
Power Take-Off, Overhaul. Removed
(Refer to appropriate PTO model to the right)
PTR-D
0.4 hr
PTR-DH
1.8 hr
PTR-DM
1.8 hr
PTR-F
0.8 hr
PTR-FH
1.6 hr
PTR-FL
1.8 hr
PTRD-D
1.4 hr
4814-19-03-01
Solution visibility
PTRD-D1
1.4 hr
PTRD-D2
1.4 hr
PTRD-F
1.4 hr
Power Take-off Shaft, Remove-Install, All Models
0.4 hr
Dealer distribution
Function(s)/component(s) affected
Function affected
Air System , Air Dryer , PTO
Function Group
Function Group
481 power-take off (gearbox) , 483 control power take-off
Customer effect
Main customer effect
fluid , diagnostics/methodology
Noise
grinding , whine , hissing noise , blowing noise
Fluid problem
leak
Fluid implicated
Transmission Oil
Visual appearance
leaking
Conditions
Vehicle operating mode
Frequency of occurrence of
problem
Location of problem
with a PTO
random
underneath cab
Administration
Author
UT9268H
Dealer ID
UT9268H
Last modified by
RU4469V
Creation date
29-08-2019 17:08
Date of last update
14-10-2019 20:10
Review date
31-12-2019 00:12
Status
Published
NA_Reviewer
UT9268H
NA_Author_Group
GTT
Variantes Kola
5XX - PTO
TRANSMISSION
MOUNTED ADM.
T4X - PTO TRANSM.
PTOTRA-S - SINGLE PTO TRANSMISSION , PTOTRA-D - DOUBLE PTO
TRANSMISSION
PTR-F - REAR PTO TRANS. FLANGE, 100% SPEDD , PTR-FL - PTO TRANS.
MOUNTED
MOUNTED REAR, FLANGE, LOW SPEED , PTRD-D1D - REAR PTO TRANS,
DOUBLE,1 DIN-CONN.PUMP+1 FLANGE DIN 120 , PTR-D - REAR PTO TRANS.,
DIN-CONN.PUMP , PTR-DH - REAR PTO TRANS., DIN-CONN.PUMP, HIGH
SPEED , PTR-DM - REAR PTO TRANS., DIN-CONN.PUMP,MEDIUM SPEED , PT
RD-F - REAR PTO TRANS., DOUBLE, 1 SAE FLANGE , PTRD-D - REAR PTO
TRANS., DOUBLE, 2 DIN-CONN.PUMP , PTRD-D2 - REAR PTO TRANS.,
DOUBLE, 1 DIN-CONN.PUMP + 2 FLANGES
RTX - AUTOMATIC
GEARBOX
TRA-AMT
UNCONTROLLED COPY. Printed document is for temporary use only and should not be retained.