2

action

plans

are

implemented

through

an

iterative

process

of

regular

oil

sampling,

development

of

trends,

problem

identifcation,

investigation

and

troubleshooting,

corrective

action,

feedback

and

review.

Trends

are

analysed

on

a

regular

basis

with

a

view

to

come

up

with

sustainable

solutions

to

any

chal

lenges

affecting

the

feet

.

THE

IMPACT

OF

WET

WEATHER

OPERATIONS

The

Wet

weather

operations

have

posed

several

chal

lenges

with

the

feet

drive

trains.

The

high

failure

rate

on

drive

trains

during

the

wet

season

and

period

fol

lowing

the

wet

season

poses

a

high

risk

and

therefore

provides

a

compel

ling

reason

for

a

case

study

and

a

formulation

of

strategies

to

protect

the

axles/drive

trains,

minimise

failures

and

improve

equipment

reliability.

This

case

study

is

an

analysis

of

this

phenomenon.

A

number

of

techniques

such

as

the

5-Why

analysis

are

used

to

try

and

get

to

the

bottom

or

root

cause

of

the

problem.

Some

of

the

questions

asked

in

this

analysis

are:

1.

How

are

wear

patterns

spread

throughout

the

year?

2.

Any

seasonal

trends?

3.

Any

changes

in

the

lubricant

in

use?

4.

Are

there

any

changes

in

tonnage

ferried

by

the

feet

per

load?

5.

Any

changes

in

intensity

of

operation?

6.

Is

this

a

feet-wide

problem

or

only

affecting

a

few

machines

of

the

same

make

&

model?

7.

Are

there

any

changes

in

operating

conditions/

road

conditions/field

conditions

and

so

on?

Where

the

answer

is

yes,

the

5-Why

analysis

principle

and

other

techniques

are

applied

to

test

and

critical

ly

analyse

the

aspect

or

factor,

in

order

to

establish

the

root

source

of

the

problem.

ANALYSIS

OF

MPE

AND

WEAR

ON

DIFFERENTIALS

AND

FINAL

DRIVES:

CASE

STUDY

OF

ZT49

DIFFERENTIAL

(AUGUST

2017)

For

simplicity

of

analysis,

the

case

of

ZT49

differential

is

used

to

il

lustrate

the

fndings

characterising

the

phenomenon,

though

the

chal

lenges

are

spread

across

the

feet

.

differential

oil

analysis

results

showed

a

repeat

problem

on

the

Microscopic

Particle

Examination

(six

times).

Large

wear

metal

particles

rose

from

1

877

MgFe/L

(sample

1)

to

13

297

MgFe/L

(Sample

2)

towards

the

end

of

the

rainy

season,

see

fol

lowing

graph:

14000

12000

10000

8000

6000

4000

2000

0

1

2

3

4

5

1877

13297

1947

3053

4271

PQ

MgFe/L

Sample

Number

Feedback

provided

by

the

customer

indicates

that

when

the

tractor

was

stuck

in

the

feld,

the

operator

repeatedly

tried

to

drive

it

out

,

resulting

in

differential

damage

before

the

tractor

was

eventual

ly

pul

led

out

of

the

feld.

It

was

also

reported

that

the

tractor

had

experienced

a

broken

propel

ler

shaft

.

The

differential

was

then

scheduled

for

replacement

.

Oil

analysis

results

show

that

this

trend

is

commonly

experienced

across

the

feet

during

periods

of

wet

weather

operation

as

wel

l

as

periods

fol

lowing

the

wet

season.

An

analysis

of

feedback

submitted

indicated

the

fol

lowing

common

observations: