FSB 431-010

Mack Trucks, Inc.
Greensboro, NC USA
Field Service Bulletin
Trucks
This Field Service Bulletin replaces bulletin FSB 431-010 dated 1.2015.
Date
Group
No.
Release
Page
4.2015
431
010
02
1(36)
Range Synchronizer, Repair
CHU, CXU
FSB 431-010, Range Synchronizer, Repair
(April 2015)
This procedure is to repair mDrive transmissions in the field that exhibit a grinding noise when
the transmission range shifts (for example: between 6th and 7th gear) built between 01/01/
2013 and 08/18/2014.
Required Parts
mDrive Range Synchronizer Repair Kit, Part Number 85020354
TECU main software equal to or greater than 22357273
Optional Parts
Note: The assembly should be disassembled and inspected before ordering optional parts.
Range Shift Fork, Part Number 21510395
Set Screws, Part Number 1652847
Required Tools
Special tools: 9809726, 9990027, 9992619, 9992671, 9992884, 9996315, 9996876,
9996889, 9996917, 9998051, 9998542, 85108826, 88800015
Premium Tech Tool version 2.03.60 or higher
Vocom Diagnostic Connector 88890304
Communication Interface 88890300
Note: Using other interfaces may affect programming speed.
Note: Check Premium Tech Tool version by clicking on Help tab and then click on “About
Tech Tool”.
PV729-FSB431-010_M
USA70647
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
Failed Parts
W4096430
The synchronizer ring is missing the high range friction material and the low range side is
wearing away.
Procedure
You must read and understand the precautions and guidelines in Service Information,
Function 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.
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.
DANGER
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.
Page
2(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
Note: Special tools: 9809726, 9990027, 9992619, 9992671, 9992884, 9996315, 9996876,
9996889, 9996917, 9998051, 9998542, 85108826, 88800015
1 Use Premium Tech Tool (PTT) to perform operation 4000-08-03-11 “Gear activation,
control housing (for removal/replacement)”. Follow the instructions in PTT.
Note: If Tech Tool is unable to activate the necessary gears for control housing removal,
follow the manual activation steps outlined in this procedure after transmission removal.
2 Secure the vehicle for service by parking it on a flat level surface, applying the parking
brake, chocking the rear wheel, and placing the transmission in neutral.
3 Disconnect all cables from the negative (ground) battery terminals to prevent personal
injury from electrical shock and prevent damage to electrical components.
4 Drain the air system.
5 Raise the vehicle and support with jack stands.
Page
3(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
6 Drain the transmission oil into a suitable container.
WARNING
Hot transmission oil can cause burns. DO NOT allow hot transmission oil to contact the
skin. When changing transmission oil, wear protective gloves.
CAUTION
Always dispose of lubricants (engine oil, coolant, transmission oil, etc.) and filters
according to Federal or local regulations. Dumping used oil or coolant on the ground or
in waterways can contaminate our drinking water and kill wildlife.
W4002889
T4022639
Page
4(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
7 Remove the transmission. Refer to Function Group 431.
8 Remove the control housing mounting bolts.
W4002951
9 Remove the six TECU mounting bolts.
Note: It is only necessary to perform this step if manually performing the “Gear activation,
control housing (for removal/replacement)”. If PTT activated the necessary gears, proceed
to step 13.
W4002952
Page
5(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
10 Manually perform the “Gear activation, control housing (for removal/replacement)” as
outlined in the next three steps.
Note: The next three steps are performed only if Tech Tool could not activate the
necessary gears for control housing removal.
11
CAUTION
Electrical components, including the wiring harness inside the transmission control
housing, are delicate. Handle with extreme care. Failure to do so may result in damage
to components.
Gently lift the top edge of the upper cover and angle it down carefully against the clutch
housing. Carefully disconnect the electrical connection and remove the top cover.
Note: Do not apply tension or weight to the wiring harness or connector.
W4002953
Page
6(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
12 Using compressed air, apply air pressure to the appropriate bore holes to place the
transmission gears in the proper position for control housing removal.
Note: It is necessary to rotate the input shaft while engaging the splitter section to mesh
the gears.
Note: It is necessary to rotate the output shaft while engaging the range section to mesh
the gears.
Note: It is necessary to rotate the output or input shaft while engaging reverse to mesh the
gears.
Note: For over drive transmissions, the transmission must be positioned as follows:
* Low Split
* High Range
* 2nd/3rd — Neutral Position
* 1st/Reverse — Reverse Position
W4002895
Over Drive Transmission
1 – High Range
2 – 3rd Gear
3 – Low Range
4 – 2nd Gear
5 – 1st Gear
6 – High Split
7 – Reverse Gear
8 – Low Split
Page
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Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
Note: For direct drive transmissions, the transmission must be positioned as
follows:
* High Split
* High Range
* 2nd/3rd — Neutral Position
* 1st/Reverse — Reverse Position
W4002895
Direct Drive Transmission
1 – High Range
2 – 3rd Gear
3 – Low Range
4 – 2nd Gear
5 – 1st Gear
6 – Low Split
7 – Reverse Gear
8 – High Split
Page
8(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
Note: If 2nd or 3rd gear is engaged, it will be necessary to position that gear set to neutral
before attempting to engage reverse.
Note: To engage neutral for the 2nd/3rd gear set, it will be necessary to gently apply air to
the bore holes. If too much air is applied, it will engage one of the two gears. To aid
positioning, do not rotate the shaft when attempting to position this gear set.
T4021451
Page
9(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
13
CAUTION
Gentle consistent pressure should be used to lift the control housing from the
transmission. Applying excessive force is not necessary or needed, and may result in
damage to components.
CAUTION
Always install the alignment pins before removing the control housing to prevent
damage to the transmission main shaft speed tone ring and the shift control.
Note: Use tool 9996876.
Install the alignment pins through the control housing into the transmission. Using a pry
bar, gently separate the control housing from the locating pins on the transmission, then
remove the control housing.
Note: If the control housing does not separate from the transmission while applying gentle
pressure upward, it may be necessary to refer back to Step 11 or Step 12 before
attempting control housing removal again.
Note: Exercise care during removal to keep from damaging the tooth wheel in the
transmission.
W4002955
Page
10(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
14 Remove the plug, spring and plunger for the range function. If necessary use a magnet to
pull out the plunger.
C4052785
15 Remove the range housing mounting fasteners.
16 Use press tool to separate the main housing and range housing.
W4088216
1. 9998051
Page
11(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
17 Carefully lift the range housing away from the main housing.
CAUTION
Ensure that the range cylinder piston rod does not jam in the main housing. Damage to
the shaft may result.
18 Remove the range gear fasteners.
T4021492
Page
12(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
19 Mark the orientation of the fork shaft to the synchronizer ring. Remove the range gear.
Note: Gear must be in high range for removal. If difficult to remove, lift on the shaft and tap
down on the housing with a dead blow hammer.
T4021493
Page
13(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
20 Remove the selector fork. Check the brass shifter pads. If the brass shifter pads are
damaged or worn, replace the fork. Tighten the set screws to 75 ±7 Nm (55 ±5 lb-ft) and
stake set screws.
Note: After staking, set screws are one time use only.
T4023050
W4096194
The fork should be replaced if there is this type of damage.
Page
14(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
W4096195
Properly Staked Set Screws
Page
15(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
21 Remove the oil return pipe.
T4021428
22 Remove the retaining ring.
T4021426
23 Remove the washer.
T4021427
24 Install the puller rings.
T4021425
Page
16(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
25 Install one half of the puller on puller rings together with the hydraulic cylinder, spindle and
drift.
Note: Check that the divide in the puller rings is at 90° to the divide in the puller.
T4021429
W4089791
1. 88800015
2. Puller Ring
3. 9998542
4. 90° Position for Tool
5. Tool Set on Puller Ring
Page
17(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
26 Install the other half of the puller and the hydraulic pump. Remove the high range
engaging ring.
W4097639
27 Clean and inspect all components.
Note: The synchronizing ring (B) must not be washed.
T4028370
Page
18(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
28 Check the part number of the spacer. If the part number is 20533124 then replace the
spacer with a new spacer included in the kit.
W4089323
Note: The next four steps are required ONLY if the spacer is replaced.
29 Remove the rear cover for the main shaft and where applicable oil pipe for overdrive gear.
T4021434
Page
19(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
30 Remove the adjustment shim for the main shaft.
W4088866
1. Shim
2. Spacer
W4089450
Spacer
31 Remove the spacer with a suitable tool and replace with the spacer included in the kit.
32 Reinstall the shim and the rear cover. Tighten fasteners to 48 ±5 Nm (35 ±4 ft-lb).
Page
20(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
33 Press in a new high range engaging ring.
W4101437
1. 9996315
2. 9992671
3. 9998542
4. 9996917
5. 88800015
6. 9809726
7. 9992884
34 Install both washer halves.
T4021427
Page
21(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
35 Install the retaining ring from the kit.
Note: There are several rings in the kit. Install the thickest ring that will seat correctly in the
groove.
T4021426
36 Oil and install O-rings. Install the oil return pipe. Tighten to 250 ±50 Nm (184 ±37 lb-ft).
T4021428
37 Clean old sealant off the range housing.
38 Lubricate sliding surfaces and O-rings with transmission fluid during assembly. It is
important to lubricate the carbon fiber lining on synchronizing ring (B).
T4028370
Page
22(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
39 Lubricate the short end of the shaft before installation. Install the engaging ring and
selector fork on the ring gear. Use the orientation mark to properly align new parts.
T4028364
40 Install the package in the range housing. Tighten the fasteners diagonally to 110 ±10 Nm
(81 ±7 lb-ft).
T4021492
Page
23(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
41 Apply a bead of approved sealant to the housing face as shown.
W4089451
42 Line up the piston rod and planetary gear. Carefully lower the range housing into the main
housing.
43 Install the range housing mounting fasteners. Tighten fasteners to 110 ±10 Nm (81 ±7 lbft).
44 Check that the control housing sealing surface is clean. Install a new control housing
gasket.
Note: Clean any dirt and corrosion from the alignment dowels in the housing and from the
dowel holes in the control housing assembly to aid in reinstallation.
Page
24(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
45 Ensure that the split engaging ring is in its rear most position. Ensure that the 2nd/3rd
engaging ring is in neutral or middle position and that the reverse gear engaging ring is in
its rear most position (Figure 1). Also ensure that the range gear is in high range (Figure
2).
Note: Ensure that the new control housing forks correspond to the position of the
engaging rings. If they do not correspond, gently position them by hand.
T4021451
Figure 1
HR – High Range
S – Split
2/3 – 2nd/3rd gear in neutral
R – Reverse gear
W4002948
Figure 2
Page
25(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
46 Ensure that the range servo piston is positioned out 25.4 mm (1 in.) to properly mate with
the main housing.
W4002950
47
CAUTION
Always install the alignment pins before installing the control housing to prevent damage
to the transmission main shaft speed tone ring and the speed sensor.
Install the alignment pins in the transmission.
T4018982
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26(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
48
CAUTION
To avoid component damage gently install the control housing with little more than
gentle taps to seat in place. If the control housing does not install easily, remove and
check the alignment of components in the gearbox and the control housing assembly.
Forcing the control housing can cause unrepairable damage and requires a component
replacement.
Carefully lower the control housing to avoid damaging the tooth wheel in the transmission.
Ensure that the split fork ends up in the correct position in engaging ring. Remove the
alignment pins.
W4002949
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Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
49 Installed new solenoid valve seals, an O-ring for the counter-shaft brake and a new upper
cover gasket.
Note: Only perform this and the following steps if; the control housing was replace without
a new upper cover. If replacing the control housing as a complete assembly proceed to 52.
T4020778
Page
28(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
50
CAUTION
Electrical components, including the wiring harness inside the transmission control
housing, are delicate. Handle with extreme care. Failure to do so may result in damage
to components.
Place the new upper cover in position and carefully connect the wiring harness. Lower the
upper cover into position.
Note: Do not apply tension or weight to the wiring harness or connector.
W4002953
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29(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
51 Install the six upper cover mounting bolts. Tighten fasteners to 24 ±4 Nm (18 ±3 ft-lb).
W4002952
52 Install the control housing. Tighten the fasteners to 110 ±10 Nm (81 ±7 ft-lb).
W4002951
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30(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
53 Connect the clutch control valve air supply tube to the upper control housing fitting.
W4002947
54 Install the plunger, spring and plug for the range function. Tighten plug to 55 ±8 Nm (41 ±6
lb-ft).
55 Connect the clutch valve wiring connector to the control housing.
W4002881
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31(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
56 After the control housing has been installed, use PTT to perform calibration operation
4000-07-04-01 “Gearbox (Gearbox removed)”.
Note: If calibration fails, check that the shift fork position sensor values are within the
specification ranges. Shift fork values out of range may indicate incorrect assembly of shift
forks to engaging rings preventing correct transmission shifting. Perform tests in PTT to
check Range cylinder (4320-08-03-02), Split cylinder (4320-08-03-03), Gear selector
cylinder 2/3 (4320-08-03-05) and Gear selector cylinder 1/Reverse (4320-08-03-24).
Remove control housing and inspect shift fork and engaging ring positions. Repeat the
control housing installation.
Note: If software needs to be updated, do NOT program gearbox until after all assembly is
complete.
57 To aid transmission installation, remove the service plug on the clutch control valve
assembly. Clean around the plug prior to removal to prevent debris from entering the
valve. Place a clean shop rag over the open port to prevent debris from entering the valve
during installation. Once the installation is complete replace the plug and tighten to 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 flywheel housing mating surface.
58 Carefully install the transmission and align to the engine. Loosely install two upper and two
lower transmission-to-engine mounting bolts to hold the transmission in place.
Note: Do NOT lubricate the input shaft splines.
Note: The use of an assistant may be necessary to aid during installation.
Note: Rotate the input shaft to align the clutch splines.
T4021203
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32(36)
Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
59 Install the remaining transmission-to-engine mounting bolts. Tighten to 92 ±8 Nm (68 ±6 ftlb). 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.
60 Position the battery cables and install their mounting bolts.
61 Position the electrical harness and reconnect the control housing, speed sensor and two
chassis connectors.
W4002941
62 Install new tie straps to secure the wiring harness to the transmission.
63 Connect the air supply hose at the rear of the transmission.
W4002940
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Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
64 Connect the transmission oil cooler hoses to the filter housing.
W4002894
65 Install the drive shaft, 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.
* Intermediate Bearing: 105 ±20 Nm (78 ±15 ft-lb)
* Universal Joint Caps: 170 ±15 Nm (125 ±10 ft-lb)
66 Remove the supporting jack stands and lower the vehicle.
67 Pressurize the air system and check for leaks.
68 Connect all previously removed cables to the negative (ground) battery terminals. Tighten
fasteners to 20 ±2 Nm (15 ±1.5 ft-lb).
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Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
69 Replace the transmission oil filter.
W4002908
70 Fill the transmission with approved transmission oil.
71 Use PTT to check the transmission electronic control unit (TECU) software, current main
software is 22357273. If the software is not current, program the TECU. From the Main
Menu select Program and then Program Electronic Control Unit 1700-08-03-39. Then click
Start. Select Transmission ECU (TECU). Select Program to update the TECU with the
latest software.
72 Use PTT to perform calibration operation 4320-07-03-01 “Gearbox, clutch, engagement
point”.
73 Clear all diagnostic trouble codes (DTC) prior to returning to service.
Page
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Mack Trucks, Inc.
Field Service Bulletin
Date
4.2015
Group
No.
Release
431
010
02
Page
36(36)
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.
Reimbursement
UCHP
Reimbursement
eWarranty
Claim Type (used only when uploading from the Dealer Bus. Sys.)
01
01
Primary Labor Code
4319-16-09-01 —
7.7 hrs.
3231N-43-80 — 7.7
hrs.
Causal Part
21480996
21480996
Labor Code
Mack Trucks 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.