NHTSA ID Number: 10183722
Manufacturer Communication Number: SI 3147
TSB/Document Date: 2020-12-05
Summary
Technical instruction describing the procedure to replace damaged seals in the cooling fan drive gearbox manufactured by Curtis Machine Company Inc.
Subject: Curtis Gear Box Seal & Gasket Replacement
Field change Program:
Service Bulletin
Coach Section:
06-Cooling
Bulletin Number: Revision:
3147
A
P/N:
06-06-1817
Date:
11/25/2020
Type:
Service Information
Application:
Coach Model
Model Year
VIN
J4500
2017
68012 - 68117, 68119 - 68148, 68150 - 68178
Read this entire procedure before beginning work.
Use Safe Shop Practices at All Times.
To avoid personal injury:
a. Proper Personal Protective Equipment (PPE) must be worn. Safety glasses and
protective gloves are required for working with DEF Fluid.
b. Turn the main battery disconnect switch to the OFF position.
c. Ensure that both the front and the rear wheels are chocked.
d. Position the ENGINE RUN and ENGINE START switches on the engine
compartment remote control box to the OFF position.
e. Allow enough time for components to cool down prior to working in the engine
compartment.
SI 3147
Curtis Gear Box Seal & Gasket Replacement
1.0
Description
This procedure outlines steps to replace damaged seals in the cooling fan drive gearbox
manufactured by Curtis Machine Company Inc.
2.0
Material requirements
Refer to Sections 5.1, 6.1 and 7.1.
3.0
Special tools
Blue adhesive Loctite, MCI
P/N: 21-7212-18.
4.0
Procedure
4.1
Removing the radiator
Drain the engine coolant following steps in Section-6 of MCI maintenance manual.
Open radiator door.
Open radiator door
Remove and save the four bolts securing the bolt-on tube assembly to the frame.
Remove and save
the four bolts
Motor Coach Industries Ltd.
Page 2 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and save the four hose clamps securing the charge air cooler (CAC) hoses and
coolant hump hoses to the radiator.
Remove and save the hose
clamps
Remove the drain tube from the frame.
Remove drain tube
from the frame
Remove and save the four bolts securing the driveshaft to the clutch.
Remove and save the bolts
Motor Coach Industries Ltd.
Page 3 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and save the eight bolts securing the radiator to the coach frame.
Remove and save the bolts
Using a forklift move the radiator from the coach and use a jack stand to support the
gearbox.
Ensure extreme caution while moving the radiator using forklift to avoid accidents
and injury. Place the radiator on wooden blocks and support the gearbox on the
jack stand to avoid the radiator tipping and injuring the operator.
Motor Coach Industries Ltd.
Page 4 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
4.2
Inspection
Inspect for oil leaks at the gaskets, seals on the gearbox ends connected to the fan and
driveshaft as shown below.
Seal #1- Fan end
Gaskets
Seal #2- Driveshaft end
If there is a leak near the seal #2, perform Section 5.0*.
If there is a leak near the gaskets, perform Sections 6.0.
If there is a leak near the seal #1, perform Section 7.0.
*If the gaskets are also leaking, skip section 5.0 and perform section 6.0, as the gaskets
replacement also requires driveshaft end seal replacement.
Motor Coach Industries Ltd.
Page 5 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
5.0
Replacing the seal on the driveshaft end
5.1
Material requirements
ITEM PART NO
QTY U/M
DESCRIPTION
1
06-06-1769 1
EA
Seal kit- Fan Gearbox, Curtis
This kit contains both seals on the gearbox (driveshaft end and fan end). Do not order
another kit if you must perform Section 7.0.
5.2
Removing the existing seal
Remove and save the bolts securing the fan drive support.
Remove and save
the bolts and fan
drive support
Remove and save the four bolts securing the driveshaft to the end yoke.
Remove and
save the bolts
Motor Coach Industries Ltd.
Page 6 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and save the yoke.
Remove and
save the yoke
Remove the seal using a narrow punch or thin-bladed screwdriver to punch a hole in it,
then pry the seal out.
Remove the seal
using a thin bladed
screwdriver
5.3
Installing the new driveshaft seal
Apply a thin film of epoxy sealer around the outside diameter of the smaller seal, part of
the seal kit, MCI P/N: 06-06-1769, and install it to the gearbox by tapping the seal gently
using a hammer evenly until it is flush with the cap.
Apply epoxy sealer
around the smaller seal,
part of 06-06-1769, and
install it to the gearbox
Page 7 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
CAUTION
Applying excessive force while tapping the seal will result in the seal getting
damaged.
Re-install the yoke to the gearbox using the key, flat washer, castle nut, and cotter pin
supplied with the gearbox. Torque the castle nut to 130 Ft-Lb. Tighten nut to align cotter
pin.
Re-install the yoke to the
gearbox using the key, flat
washer, castle nut and cotter
pin supplied with gearbox
CAUTION
Do not loosen the nut to align the cotter pin.
Re-install the driveshaft to the end yoke using existing strap kits. Torque the nuts to 28
Ft-Lb.
Re-install
driveshaft using
existing strap kits
Page 8 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Re-install the fan drive support using existing bolts and nuts, as shown below. Torque the
nuts to 45 Ft-lb.
Re-install the fan
drive support using
existing bolts and
nuts
6.0
Replacing the gaskets
6.1
ITEM
1
2
6.2
Material requirements
PART NO
06-06-1769
06-06-1772
QTY U/M
1
EA
1
EA
DESCRIPTION
Seal kit- Fan Gearbox, Curtis
Gasket Kit- Fan Gearbox, Curtis
Removing the existing gaskets
Remove and save the bolts securing the fan drive support.
Remove and save
the bolts and fan
drive support
Motor Coach Industries Ltd.
Page 9 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and save the four bolts securing the driveshaft to the end yoke.
Remove and
save the bolts
Remove and save the yoke.
Remove and
save the yoke
Remove the seal using a narrow punch or thin-bladed screwdriver to punch a hole in it,
then pry the seal out.
Remove the seal
using a thin bladed
screwdriver
Motor Coach Industries Ltd.
Page 10 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and the bolts securing the hub. Remove the hub.
Remove and save
the bolts
Remove and discard the existing gaskets. Make note of the gasket size(s).
Remove and
discard the gaskets
6.3
Installing new gaskets
Install the new gaskets part of the gasket kit, MCI P/N: 06-06-1772, of similar size as the
discarded gaskets.
Install gaskets part of
gasket kit, 06-06-1772
Motor Coach Industries Ltd.
Page 11 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Re-install the hub using existing bolts and torque them to 35 Ft-Lb. Ensure to tighten the
bolts in a cross fashion, as shown below.
1
4
7
6
Re-install the hub
and torque the bolts
to 35 Ft-Lb
3
2
5
6.3
8
Installing the new driveshaft seal
Apply a thin film of epoxy sealer around the outside diameter of the smaller seal, part of
the seal kit, MCI P/N: 06-06-1769, and install it to the gearbox by tapping the seal gently
using a hammer evenly until it is flush with the cap.
Apply epoxy sealer
around the smaller seal,
part of 06-06-1769, and
install it to the gearbox
CAUTION
Applying excessive force while tapping the seal will result in the seal getting
damaged.
Motor Coach Industries Ltd.
Page 12 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Re-install the yoke to the gearbox using the key, flat washer, castle nut, and cotter pin
supplied with the gearbox. Torque the castle nut to 130 Ft-Lb. Tighten nut to align cotter
pin.
Re-install the yoke to the
gearbox using the key, flat
washer, castle nut and cotter
pin supplied with gearbox
CAUTION
Do not loosen the nut to align the cotter pin.
Re-install the driveshaft to the end yoke using existing strap kits. Torque the nuts to 28
Ft-Lb.
Re-install
driveshaft using
existing strap kits
Motor Coach Industries Ltd.
Page 13 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Re-install the fan drive support using existing bolts and nuts, as shown below. Torque the
nuts to 45 Ft-lb.
Re-install the fan
drive support using
existing bolts and
nuts
7.0
Replacing the seal on the fan end
7.1
Material requirements
ITEM PART NO
QTY U/M
DESCRIPTION
1
06-06-1769 1
EA
Seal kit- Fan Gearbox, Curtis
This kit contains both seals on the gearbox (driveshaft end and fan end)
7.2
Removing the existing seal
Remove the eight screws securing the frame and gearbox assembly to the radiator.
Remove and
save the bolts
Motor Coach Industries Ltd.
Page 14 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Support the radiator when gearbox assembly is separated to avoid damage to the
radiator and personal injuries to the operator.
Remove and save the six bolts securing the fan hub to gearbox.
Remove and
save the bolts
Motor Coach Industries Ltd.
Page 15 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Remove and save the nut and washer securing the fan hub. Remove and save the fan
hub.
Remove and save
nut, washer and fan
hub
Remove the seal using a narrow punch or thin-bladed screwdriver to punch a hole in it,
then pry the seal out.
Remove the seal
using a thin bladed
screwdriver
Motor Coach Industries Ltd.
Page 16 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
7.3
Installing new seal
Apply a thin film of epoxy sealer around the outside diameter of the smaller seal, part of
the seal kit, MCI P/N: 06-06-1769, and install it to the hub cap by tapping the seal gently
using a hammer evenly until it is flush with the cap.
Apply epoxy sealer
around the smaller seal,
part of 06-06-1769, and
install it to the hub cap
CAUTION
Applying excessive force while tapping the seal will result in the seal getting
damaged.
Re-install the fan hub to the gearbox using the existing washer and nut. Torque the nut
to 130 Ft-Lb.
Re-install the fan
hub using existing
washer and nut
Page 17 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Add Loctite, MCI P/N: 21-7212-18, to the existing bolts and re-install the fan. Torque the
bolts to 34 Ft-Lb.
Re-install fan using
existing bolts
Re-install the frame and gearbox assembly to the radiator door using existing bolts.
Torque the bolts to 44 Ft-Lb.
Re-install the frame
and gearbox assembly
to radiator door using
existing bolts
Page 18 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
8.0
Re-installing the radiator
Apply Loctite, MCI P/N: 21-7212-18, to the existing bolts and re-install the radiator.
Torque the bolts to 130 Ft-Lb.
Re-install the radiator to coach
frame using existing bolts
Ensure extreme caution while moving the radiator using forklift to avoid accidents
and injury.
Apply Loctite, MCI P/N: 21-7212-18, to the existing bolts and re-install the driveshaft to
the clutch. Torque the bolts to 57 Ft-Lb.
Re-install the fan drive
using existing bolts
Motor Coach Industries Ltd.
Page 19 of 20
SI 3147
Curtis Gear Box Seal & Gasket Replacement
Re-install the CAC hoses using existing clamps. Torque the top clamps to 100 In-Lb and
bottom clamps to 115 In-Lb.
Re-install the CAC hoses
using existing clamps
Re-insert the drain tube into the grommet in coach frame.
Re-insert the drain
tube into the grommet
Re-install the bolt-on tube assembly to the frame using existing hardware. Torque them
to 119 Ft-Lb.
Reinstall the tube
assembly
End of the procedure
Motor Coach Industries Ltd.
Page 20 of 20
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TSB/Document ID: SI 3147
Replacement Service Bulletin Number:
MFR Communication Date: 2020-11-30
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ENGINE AND ENGINE COOLING
MFR Component System:
MFR Component Subsystem:
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