Replace damaged components.
ProStar/PayStar models: proceed to
Step 4.
TranStar models: proceed to Step 5.
A. No
B. Either Yes or No
Create iApproval form for an engine
replacement, continue to step 6.

Step Action
Perform the following:

4

A. Perform Fan Drive Retrofit (see Step 8)
B. Replace oil & filter
C. Replace Centrifugal filter
D. If necessary replace oil pump (see Other Inspection Guidelines section
below)
E. If necessary replace gears in front gear train (see Other Inspection
Guidelines section below)
F. If necessary replace oil cooler (see Other Inspection Guidelines section
below)

Decision
Yes: Complete repairs as needed and
return vehicle to customer.

No: Release vehicle to customer.

Run engine fan test and inspect for leaks or any other damage. Are there any
other repairs needed?

Step Action
Perform the following:

5

A. Replace fan drive
B. Replace oil & filter
C. Replace Centrifugal filter
D. If necessary replace oil pump (see Other Inspection Guidelines section
below)
E. If necessary replace gears in front gear train (see Other Inspection
Guidelines section below)
F. If necessary replace oil cooler (see Other Inspection Guidelines section
below)

Decision
Yes: Complete repairs as needed and
return vehicle to customer.

No: Release vehicle to customer.

Run engine fan test and inspect for leaks or any other damage. Are there any
other repairs needed?

Step Action
Perform the following:
6

Decision
Yes: Complete repairs as needed and
return vehicle to customer

A. Replace the engine.
Is the chassis being worked on a TranStar?

No: Continue to Step 7.

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IK0900115 - Fan Shaft Failure Diagnostics

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Step Action

Decision

Perform the Following:
7

Yes: Install chassis kit. Refer
to retrofit instruction sheet.

A. Inspect replacement engine
No: Complete all necessary repairs and
release vehicle to customer.

Does replacement engine have 2-speed fan drive equipped?

Step Action

Decision

FAN DRIVE RETROFIT:

8

Yes. Complete all other repairs as
needed.

Reference IK0900105: Retrofiting a Horton VMaster(Stratis) fan drive to Horton
2spd air operated fan drive.
No. Repeat step.
Was fan drive retrofit and programming successful?

OTHER INSPECTION GUIDELINES
Action

Decision

OIL PUMP GEROTOR AND OIL COOLER REUSE OR REPLACE
DETERMINATION:

Yes. Replace gerotor and oil cooler.

Inspect oil pump gerotor. See Figures 4 and 5 for examples of damage.
NOTE: there may be some light scoring on the block behind the oil pump as
pictured in Figure 6. This amount is acceptable and will not lead to loss of oil
pressure or engine performance/longevity as long as gear end play is in spec. No. Complete all other repairs as needed.
However, this scoring does indicate that the oil cooler must be replaced.
End play between the oil pump cover and oil pump gears must be measured while
inspecting the oil pump. This procedure is outlined in the Engine Service Manual
found on the Master Service Information Site. If end play exceeds specification,
replace oil pump cover, pinion (gear) for oil pump, and ring gear as a set.

Is the gerotor damaged?

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Figure 4: Damaged oil pump/gerotor

Figure 5: Damaged oil pump/gerotor

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IK0900115 - Fan Shaft Failure Diagnostics

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Figure 6: Acceptable engine block wear behind oil pump

Action

Decision

FRONT GEAR TRAIN INSPECTION AND OIL COOLER REUSE OR REPLACE
DETERMINATION:

Yes. Replace damaged gears and oil
cooler.

While the front cover is off, inspect remaining gears for damage.
NOTE: It is possible that gear contact to the engine block has occured. These
engine blocks should be reused, and will not lose performance/longevity. See
No. Complete all other repairs as needed.
Figures 7 and 8 for examples.
If gear contact to the engine has occured, the oil cooler must be replaced.
Are there any other gears damaged?

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Figure 7: Acceptable engine block wear
Item 1: Gear contact to the engine block

Figure 8: Acceptable engine block wear
Item 1: Gear contact to the engine block

REPAIR STEPS
Replace necessary components per Engine Service Manual.

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IK0900115 - Fan Shaft Failure Diagnostics

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Master Service Information Site

WARRANTY INFORMATION
Warranty Claim Coding:
Group: 12000 - Engine
Noun: 742 - Fan, shaft and mounting

Standard Repair Times:
Step Description

Chassis

Engine

1

Check engine oil and oil
All Models All Engines
filter for metal debris

1

Replace fan drive
(TranStar only)

8600

Qualifier

SRT
T-time

MAXXFORCE 11/13 Requires Front Cover Removal Q12­3742L
MAXXFORCE 11/13 With 2010 Emission Engines Q12-3742U
N13

With 2010 Emission Engines

Hours
0.3

Link to Hours

Q12-3742US

2

Main/rod bearing
inspection

All Models All Engines

A12-3442

3

Oil pump bushing
inspection

All Models All Engines

T-time

2.7

4A/8 Perform fan drive retrofit All Models All Engines

T-time

4.2

All Models All Engines

T-time

3.1

All Models All Engines

T-time

0.3

4/5C Replace centrifugal filter All Models All Engines

T-time

0.2

4/5D Replace oil pump

All Models All Engines

T-time

0.3

All Models All Engines

T-time

0.2

All Models All Engines

T-time

3.4

5A Replace fan drive

4/5B Replace oil and filter

4/5E

Replace gears in front
gear train

4/5F Replace oil cooler

Link to Hours

6

Replace engine

All Models All Engines

T-time

13.1

7

Install 2 speed fan drive
All Models All Engines
chassis kit

T-time

0.6

OTHER RESOURCES
Master Service Information Site

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