FSB-437-002-01

Field Service Bulletin
Trucks
Mack Trucks, Inc.
Greensboro, NC USA
SB-10044327-6332
Date
Group
No.
Release
Page
5.2012
437
002
01
1(16)
Allison Transmission Mount Replacement
LEU, MRU
MP7
FSB 437-002, Transmission Mount, Replacement
(May 2012)
Allison transmissions on LEU and MRU MACK Truck models with an MP7 engine may
experience cracks in the transmission housing under severe operating conditions. The
cracks are located where the transmission/engine supports are attached. To resolve this
issue, new frame brackets, transmission mounting brackets and mounting hardware
is available for replacement of the existing transmission mounts. Additionally, the
existing dipstick and dipstick tube assembly will be replaced due to interference of the
new transmission mounting bracket. Applicable parts and procedures for replacing the
transmission mounts are provided in this Field Service Bulletin.
Note: This bulletin does not apply to MACK Trucks Australia.
W4073826
PV729-FSB437-002_M
USA52967
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
Required Parts
W4073827
Transmission Mount Replacement Parts
Item #
Part Number
QTY
Description
1
25156623
1
Bracket Trans Mounted, Right Side
2
25167424
1
Bracket Trans Mounted, Left Side
3
21892421
2
Bracket Frame Side W/Liner
4
21892458
2
Bracket Frame Side WO/Liner
5
25155021
8
Washer
6
25167342
8
Rubber Insulator
7
25091937
4
Bolt
8
25109333
4
Nut
9
20706115
12
Washer
10
25160670
12
Bolt
11
21475322
12
Bolt 14 mm (0.5 in) x 47 mm (1.8 in) W/ Liner
12
21475321
12
Bolt 14 mm (0.5) x 42 mm (1.6 in) WO/ /Liner
13
21475706
12
Huckspin Collar
Replacement Dipstick and Dipstick Tube Assembly
Item #
Part Number
QTY
Description
1
25152437
1
Allison, Dipstick Tube
2
20925236
1
Dipstick, Transmission Oil Level
3
25195153
1
Bracket
4
3968658
1
Screw
5
25087147
1
M6 Flange Screw
6
25095637
1
Clamp
7
25161716
1
Attaching Clamp, Straight P-Clamp-Rubber
8
20706309
1
Nut
Page
2(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
Clamp Assembly
Part Number
Qty
1
995465
1
M8 x 35 Bolt
2
20960549
1
Clamp
3
990940
1
M8 Nut
4
N/A
N/A
Item #
Description
Transmission Coolant Pipe
Procedure
You must read and understand the precautions and guidelines in Service Information,
group 40, "General Safety Practices, Transmission" before performing this procedure.
If you are not properly trained and certified in this procedure, ask your supervisor for
training before you perform it.
1 Chock wheels.
2 Disconnect all cables from the negative (ground) battery terminals to prevent personal
injury from electrical shock and prevent damage to electrical components.
3 Raise the cab.
4 Use coolant extractor/injector 85112740 to drain coolant from engine and transmission.
5 Support transmission with suitable lifting device to enable access to engine/transmission
mounts.
6 Remove vertical transmission support fasteners, passenger side.
W4073828
Page
3(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
7 Remove the two rear passenger side spring hanger fasteners.
W4073829
8 Using a huck splitter tool, remove the huck fasteners securing frame mounted
transmission support and the applicable huck fasteners in the Diesel Exhaust Fluid (DEF)
tank bracket.
W4073830
9 Move the frame mounted transmission support forward of the transmission mounted
support.
10 Clip applicable cable ties and relocate frame mount forward inside the frame rail to give
access to transmission mounted support fasteners.
Page
4(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
11 Remove the transmission dipstick tube and dipstick, then discard.
Note: Plug the access hole in the transmission with an appropriate size cap after
removing dipstick tube and dipstick.
W4073831
12 Remove the fasteners securing passenger side transmission mounted support.
W4073832
Page
5(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
13 Remove transmission mounted support and frame mounted support.
W4073833
14 Position passenger side replacement frame mounted support inside the frame rail and
forward of the anticipated transmission mounted support location.
W4073834
Page
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Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
15 Position and install the replacement passenger side transmission support and fasteners.
Tighten fasteners to 244 ± 16 Nm (180 ± 12 ft-lb).
W4073835
16 Position frame mounted transmission support.
W4073836
Page
7(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
17 Install huck fasteners and collars.
W4073830
18 Using a huck fastener tool, Install new huck fasteners through the DEF tank bracket.
19 Install the two rear passenger side spring hanger fasteners.
W4073837
Page
8(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
20 Remove the two rear driver side spring hanger fasteners.
W4073838
21 Using a huck splitter tool, remove huck fasteners securing the driver side frame mounted
transmission support.
W4073839
22 Move the frame mounted transmission support forward of the transmission mounted
support.
23 Clip applicable cable ties and relocate frame mount forward inside the frame rail to give
access to transmission mounted support fasteners.
24 Remove fasteners and brackets securing wet air tank to allow tank to hang freely.
25 Remove transmission coolant pipe.
Page
9(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
26 Remove fasteners securing driver side transmission mounted support.
W4073840
27 Remove transmission mounted support and frame mounted support.
W4073841
Page
10(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
28 Position driver side replacement frame mounted support inside the frame rail and forward
of the anticipated transmission mounted support location.
W4073842
29 Position and install the replacement driver side transmission support and fasteners.
Tighten fasteners to 244 ± 16 Nm (180 ± 12 ft-lb).
W4073843
Page
11(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
30 Position frame mounted transmission support.
W4073844
31 Using a huck fastener tool, Install huck fasteners and collars.
W4073839
Page
12(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
32 Install the two rear driver side spring hanger fasteners.
W4073838
33 Install cable ties around harnesses and secure hoses at the appropriate locations.
34 Assemble the top and bottom rubber mounts, washers, and fasteners between
transmission mounted and frame mounted supports on both sides.
Note: Passenger side shown for instructional purposes.
W4073846
Page
13(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
35 Tighten vertical transmission mount fasteners to 500 Nm (368 ft-lb) on the passenger
and driver side.
W4073847
36 Install transmission coolant pipe.
37 Position the transmission coolant pipe, support clamp and fasteners on the frame mounted
transmission support, drivers side and mark the location of the support clamp hole.
Note: See table on page 3 for clamp assembly parts.
38 Drill one 8.5 mm (0.33 in) hole in the driver side transmission mounted support for the
coolant pipe clamp assembly.
39 Install coolant pipe clamp assembly.
W4073848
Page
14(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
01
40 Remove plug, install new transmission dipstick tube and dipstick assembly. See table
on page 2 for parts list.
W4073849
41 Install wet air tank, brackets, and fasteners.
42 Use coolant extraction/injector 85112740 to fill the engine and transmission with coolant.
43 Reconnect all previously removed cables to the negative (ground) battery terminals.
44 Lower the cab.
45 Remove wheel chocks.
46 Start engine, check for proper operation, and Check for leaks.
Page
15(16)
Mack Trucks, Inc.
Field Service Bulletin
Date
5.2012
Group
No.
Release
437
002
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.
Claim Type (used only when uploading from the Dealer Bus. Sys.)
W
Labor Code
Primary Labor Code
2992A-01-80
5.4 hrs.
Causal Part
21090653
MACK Trucks North America engages in a continuous program of testing and evaluating to
provide the best possible product. MACK Trucks North America, however, is not committed
to, or liable for updating existing chassis.
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