FSB 491-032

Field Service Bulletin
Trucks
Mack Trucks
Greensboro, NC USA
Date
3.2021
Group
491
No.
032
Release
01
Page
1(13)
Transmission Oil Cooler Hose, Replacement
CHU, CXU, GU, TE, PI, AN, GR
FSB 491-032 Transmission Oil Cooler Hose,
Replacement
(March 2021)
When replacing the transmission oil cooler hose on vehicles build prior to November 13th,
2020, new oil cooler hose lines will be necessary to connect the oil cooler. The new oil cooler
hoses increase the sealing capacity.
Required Parts
Quantity
Part Number
Part Description
1
23790464
Oil hose
1
23790470
Oil hose
1
23902388
Bracket
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.
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.
1 Park the vehicle on a flat and level surface.
2 Apply the parking brake.
3 Place the transmission in neutral or park.
4 Install the wheel chocks.
W7086748
PV729-FSB491-032_M
USA154738473
Mack Trucks
Field Service Bulletin
Group
Date
3.2021
491
5 Unlatch and remove the battery box cover.
6 Disconnect the cable from the battery’s negative terminal.
T3164283
.
7 Raise and support the vehicle.
8 Remove the screw and the nut.
9 Remove the clamp.
T4164285
.
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
10 Remove the screw.
11 Remove the bracket.
T4164286
12 Loosen the nuts.
T4164287
13 Move aside the hoses.
T4164288
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
14 Remove the screws along with the bracket.
15 Move aside the assembly.
T4164289
16 Remove the fittings.
Note: Discard the fittings and seals.
T4164425
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
17 Remove the hose
Note: Discard the hose, fittings and seals.
Note: Use a wrench to hold the fitting adapter from turning.
T4164290
18 Remove the hose.
Note: Discard the hose, fittings and seals.
Note: Use a wrench to hold the fitting adapter from turning.
T4164291
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
19 Remove the fittings.
Note: Discard the fittings and seals.
T4164426
20 Position the assembly.
T4164351
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
21 Install the screws
Note: Do not install the bracket.
Note: Hand tighten only.
T4164296
22 Remove the screw.
23 Install the bracket.
24 Install the screw.
25 Torque tighten the screw to 24 ±4 Nm (18 ±3 lbf⋅ft).
T4164292
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
No.
032
Release
01
26 Install the washers.
Note: Use new parts.
27 Install the hose.
T4171213
Note: Check for correct alignment of the hose.
T4171215
28 Torque tighten the hose fittings to 45 ±5 Nm (33 ±4 lbf⋅ft).
T4164365
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
No.
032
Release
01
29 Install the washers.
Note: Use new parts.
30 Install the hose.
T4171212
Note: Check for correct alignment of the hose.
T4171214
31 Torque tighten the hose fittings to 45 ±5 Nm (33 ±4 lbf⋅ft).
T4164428
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
32 Remove the bottom screw, then install the bracket along with the screw.
T4164295
33 Torque tighten the screws to 50 ±5 Nm (37 ±4 lbf⋅ft).
T4164364
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
34 Install the bracket.
35 Install the screw.
T4164286
36 Install the clamp.
37 Install the screw and the nut.
38 Torque tighten the screw to 9.9 ±1.5 Nm (88 ±13 lbf⋅in).
T4164285
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
No.
491
032
39 Connect the battery cable to the battery’s negative (ground) terminal.
40 Tighten the fastener to 21 ± 1 Nm (16 ± 1 ft-lb).
T3164283
41 Position and latch the battery box cover.
42 Start the engine and check for leaks.
43 Check the transmission oil level. Replenish with the correct fluid as needed.
44 Remove the wheel chocks.
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Mack Trucks
Field Service Bulletin
Date
3.2021
Group
491
No.
032
Release
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. 01
Sys.)
Labor Code
Primary Labor Code
4912-03-09-02
1.5 hrs
Causal Part
23701845, 23701846
Note: This only covers transmission oil cooler radiator replacements that are under warranty.
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.
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