NHTSA ID Number: 10087532
Manufacturer Communication Number: FSB 773-001
TSB/Document Date: 2016-12-29
Summary
CERTAIN MACK TRUCKS
BUILT AFTER 09/30/2016 MAY USE ONE OF 3 TYPES OF GASKETS ON THE MACK DRIVE AXLES. THE TRUCK COULD BE BUILT WITH A RUBBER O-RING, A FLAT PAPER GASKET, OR ROOM TEMPERATURE VULCANIZING (RTV) GASKET MATERIAL USE TO SEAL THE MATING SURFACES OF THE HUB AND DRIVE AXLE FLANGE. THIS DOCUMENT CONTAINS ONLY INFORMATION FOR THE ADDITIONAL WORK NEEDED DURING A PRE-DELIVERY INSPECTION (PDI) ON A VEHICLE BUILT WITH RTV USED ON THE DRIVE AXLE FLANGE GASKET.
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TSB/Document ID: FSB 773-001
Replacement Service Bulletin Number:
MFR Communication Date: 2016-10-03
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: POWER TRAIN
MFR Component System:
MFR Component Subsystem:
Previous TSB | Next TSB |
Mack Trucks
Greensboro, NC USA
Field Service Bulletin
Trucks
Date
Group
No.
Release
Page
10.2016
773
001
01
1(10)
Drive Axle Flange to Hub RTV Gasket,
Installation
CHU, CXU, GU
FSB 773-001, Drive Axle Flange to Hub RTV
Gasket, Installation
(October 2016)
Certain MACK trucks built after 09/30/2016 may use one of 3 types of gaskets on the MACK
drive axles. The truck could be built with a rubber o-ring, a flat paper gasket, or Room
Temperature Vulcanizing (RTV) gasket material use to seal the mating surfaces of the hub
and drive axle flange. This document contains only information for the additional work
needed during a Pre-Delivery Inspection (PDI) on a vehicle built with RTV used on the drive
axle flange gasket. When a MACK truck is delivered as a “Decked Unit” from Macungie, the
drive axles are removed for transport and a temporary cover is bolted to the hub to prevent
axle lubrication from leaking during transport. Upon delivery, the drive away company driver
reinstalls the drives axles with new gaskets (O-ring or paper gasket only) and hand torques
all mounting fasteners. For MACK trucks delivered with RTV, the delivery driver will reinstall
the axles and hand tighten fasteners without cleaning or installing new RTV gasket material.
Follow the steps in this document to identify and repair MACK trucks delivered with RTV
gasket during the PDI.
Note: This bulletin does not apply to MACK Trucks Australia.
W7115590
PV729-FSB773-001_M
USA79485
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
W7115834
Gasket Material
Gasket Material
Item #
Description
Part Number
Qty
1
Ultra Black RTV Silicone Gasket
Maker
N/A
1
Decommissioning the Truck for Repair
You must read and understand the precautions and guidelines in Service Information,
group 70, "General Safety Practices, Frame, Springs, Shocks & Wheels" before
performing this procedure. If you are not properly trained and certified in this procedure,
ask your supervisor for training before you perform it.
NOTE: Information is subject to change without notice. Illustrations are used for reference
only and can differ slightly from the actual vehicle being serviced. However, key
components addressed in this information are represented as accurately as possible.
DANGER
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.
Page
2(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
1 Park the vehicle on a level surface.
2 Apply the parking brake.
3 Place the transmission in neutral or park.
4 Install the wheel chocks on the rear wheels.
W7086748
5 Disconnect the cable from the battery’s negative terminal.
W3086747
Page
3(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
Drive Axle Flange to Hub RTV Gasket, Installation
1 During PDI, Identify whether or not the truck has an RTV gasket by looking for the green
colored tag with RTV written on it attached to the keys as shown in the figure below.
Note: If the green colored tag with (RTV) written on it is attached to the keys, additional
steps are required to repair the truck axle shaft flange during PDI. Proceed to step 2 for
installation of RTV gasket.
W7115835
Note: If the truck was built with an o-ring or flat paper gasket on the truck axle shaft
flange, the delivery driver will install new o-rings (part number 3199066) or flat paper
gaskets (part number 3973009) when they reinstall the drive axles.
W7115836
Page
4(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
2 Ensure the hub and axle shaft mating surfaces are dry, free of debris, burrs, and score
lines.
Note: RTV will not adhere properly with any oil on the hub or axle flange surface. Ensure
the mating surfaces are dry before applying a new bead of RTV gasket material.
W7115837
Page
5(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
3 Apply a continuous 5 mm (0.19 in) bead of Ultra Black RTV Silicone Gasket Maker to the
hub as shown in the figure below.
W7115834
W7115838
Page
6(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
4 Immediately install axle shaft onto hub mounting surface to avoid premature curing of the
RTV gasket material.
Note: The axle shaft installation may require the need to push down on the axle shaft
while rotating clockwise and counterclockwise to seat into the axle housing.
Note: Never attempt to engage the axle shaft into the axle housing by running down the
axle shaft flange nuts.
5 Install the tapered cones, washers, and lock nuts onto hub studs.
W7115839
6 If applicable, ensure differential is filled to the proper fluid level.
Page
7(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
7 Tighten the axle shaft flange lock nuts to 136 ± 20 Nm (100 ± 15 ft-lb) and in the sequence
shown in the figure below.
Drive Axle Flange Nut Torque Sequence
Fig.
Hub
A
6 Stud
B
8 Stud
C
10 Stud
W7115870
8 Ensure all residual oil is cleaned from wheel and all other surfaces after repair.
Page
8(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
Commissioning the Truck for Operation
1 Connect the cable to the battery’s negative terminal.
W3086758
2 Remove the wheel chocks from the rear wheels.
W7086759
Page
9(10)
Mack Trucks
Field Service Bulletin
Date
10.2016
Group
No.
Release
773
001
01
Reimbursement
This repair may be eligible for reimbursement if a product
failure was experienced within time and mileage limits of
the applicable Warranty coverage. Reimbursement is
obtained via the normal claim handling process.
UCHP Reimbursement
Claim Type (used only when uploading from the Dealer
Bus. Sys.)
01
Labor Code
Primary Labor Code (Drive Axle Flange to Hub RTV Gasket,
Installation)
7731-03-09-01
0.4 hrs. (Per Wheel
End)
Causal Part
3973009
MACK Trucks North America reserves the right to make any changes in design or to make
additions to or upon its products without incurring any obligations to install the same on
vehicles previously built.
Page
10(10)
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