Root Cause Analysis (RCA): Receipe for disaster

October 2006
Issue 1, Volume 5
[email protected]
www.tcraonline.com
Torque Converter Rebuilders Association
Root Cause Analysis (RCA): Receipe for disaster
By Joe Rivera
A
sk any builder or installer: the torque
converter is the root of all evil. When
a car comes back, you’re sure to hear: “I
don’t see anything wrong with the vehicle
or transmission, so it must be the torque
converter.” Of course, they could be right;
torque converters go bad. But condemning
a part without doing a proper Root Cause
Analysis (RCA) is a recipe for disaster. If
you don’t find and fix the root cause of the
problem you’re most certainly doomed to
see that vehicle again. What you really need
to look for is both the cause and the effect.
Many times when a converter goes bad, it
may only be the effect; something else is
the cause. Of course, it’s easier just to fix
what’s obvious, but the only way to avoid
having it break again is to fix both the cause
and the effect.
The effect of all of these conditions may
be the same — a converter failure — but
the cause is completely different. The reality is that if you don’t do a proper root cause
analysis when the vehicle comes in for the
initial repair or warranty, you’re almost
guaranteed a repeat of the initial failure. A
great example is when a torque converter
overheats and causes the unit to fail. During
a proper root cause analysis, you may find
more than one reason for the overheating.
Here’s why: The torque converter transfers
power from the engine to the transmission.
While doing so, it adds a certain amount
of built-in slip to the connection. That slip
through the torque converter creates heat. In fact, the converter
generates 90% or more of the total
system heat; the transmission only
creates about 8%-10%. The transmission and the cooling system
are designed to dissipate that heat.
So, if the transmission is overheating, why look at the torque converter first? Why not look at the
system that’s supposed to remove
the heat? Of course, the converter
can restrict fluid flow or pressure
and not allow the cooling system
to work the way it was designed.
This will prevent proper heat dissipation, and will increase operating temperatures to a level that can
cause failure. Another possibility is
the converter is creating heat when
it isn’t supposed to. How is that pos-
Root cause analysis (RCA) describes a method
of problem solving that stresses identifying the
source of a problem, rather than simply addressing the symptoms or effects of that problem. By
directing repairs at the root cause, you’re more
likely to repair the problem, rather than simply
compensate for it. Of course, it’s not always possible to repair a problem completely through a
single repair, so RCA is often considered to be a
repetitive process of continuous improvement.
While there is some disagreement in the actual
meaning of root cause analysis, there are some
principles and processes that could be considered universal.
General Principles of Root
Cause Analysis
1. Aiming corrective measures at
the root cause of a problem
is more effective than merely
treating its symptoms.
2. To be effective, root cause
analysis must be performed
systematically, and conclusions
must be backed up by
evidence.
3. There’s usually more than one
root cause for a problem.
sible? If the converter clutch is slipping more
than it’s designed to, it’ll generate excessive
heat. So how are you or the torque converter shop supposed to determine which came
first, the chicken or the egg? There may be
times that you won’t be able to, but many
times you can. Think about the Three C’s of
communication: If you speak Calmly, Candidly and Carefully to your customer, together you should be able to find the actual
cause of the problem and prevent customer
dissatisfaction. Communication is going to
be the key to your relationship with your
customer. Unfortunately, because we’re all
in business to make money, any warranty
item affects our bottom line, so it’s hard not
to take warranty items seriously, but try not
to take it personally. Many people would argue, “I don’t have time to do a proper root
cause analysis because the customer needs
the car right away.” Sure they need the car
fixed right away. But they need the vehicle
fixed so that it doesn’t happen again. My
answer to that is you don’t have the time
not to do it. If you repair just the effect and
not the cause, your problem isn’t time, but
that the customer will be bringing it back to
you to repair again, or worse, the customer
will take it somewhere else. Not only have
you lost a customer; you’ve damaged your
reputation.
There are two old adages that stand true:
one, history always repeats itself; two,
there is never time to do it right, but always
time to do it again. The pressures of being
in the transmission repair business can be
very stressful. Unfortunately, this stress can
interfere with solid diagnostic techniques.
If you don’t perform a proper root cause
analysis and fix the cause of the vehicle
problem, you’re destined to lose again and
again. But if you take the time to find the
real cause of the problem, there’s a good
chance the vehicle won’t come back. A good
customer once told me “The short way is
often the long way in the long run.” So, if
you don’t take the time to do a proper root
cause analysis, you’ll be doing the job again
soon… only this time, it’ll cost you.
General Process for Performing
Root Cause Analysis
1. Define the problem.
2. Gather data or evidence.
3. Identify problems that contributed
to problem (Causal
Factors).
4. Find root causes for each
Causal Factor.
5. Develop solution recommendations.
6. Implement the solutions.
Monthly publication of TCRA newsletter provided by Melissa Sneath of Melyns Print & Pro.
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Joe Rivera........................President
[email protected]
Ed Lee...................... Vice President
[email protected]
Dick Lewis.......................Treasurer
[email protected]
Chris Mann......................Secretary
[email protected]
Ken Cluck
[email protected]
Steve Jaussaud
[email protected]
Mark Mustard
[email protected]
Don Randolph
[email protected]
Dennis Sneath
[email protected]
Jan Stimmel
[email protected]
Len Wack
[email protected]
phone/fax..... (802) 885-2292
TCRA Semina
7
0
r
20
CD4E clutch designs include questionable flaws
O
ver the past years, Ford has created numerous clutch designs, including changing
the design from model to model. The frequent
changes have caused rebuilders to notice questionable design flaws and driveability issues.
In this issue we will focus on the problems associated with the CD4E, Dacco part number F70. This unit is commonly used in the 2000
and newer Ford Escape with the 3.0L engine.
The converter is easily identified by the large
letter “H” stamped in the center of the pilot.
Although this unit has not been considered
a larger
p r o b lem
by
Ford, it is
plagued
w i t h
clutchpiston
failure.
Under
close ex-
amination, cracks in the piston (see photo) are
found in many of the earlier units, most commonly in 2001 and 2002 models using the
CD4E. Poor clutch release and apply can be
contributed to this material defect, which can
lead to total clutch failure.
Unfortunately, new piston replacement parts
are unavailable through suppliers. Fortunately,
this part is plentiful in the Dacco F-68 AX4N/S.
Since new parts cannot be ordered, it is suggested to use the same component from this
converter. This converter is easily identified
from an aerial view. The turbine hub will have
three notches, as opposed to two or four commonly found on other models. Only the threenotch contains the correct replacement piston.
We do not suggest welding or machining this
part; it will only lead to failure.
While this problem does appear to be common in the CD4E, the AX4N/S version performs
crack-free. We have not concluded why the piston reacts differently between these two units,
possibly a manufacturing or vendor issue.
Taking A Closer Look...
Ford CD4E/Code “H”
Dacco Part Number
F-70
Pilot Size
.825”
Where......... Yet to be announced
Overall Height
When........................ May 2007
3.685” to 3.720”
Be sure to watch for seminar updates throughout the year, including location, speaker appearances,
facility tours and more.
Bushing Diameter
1.760” to1.768”
Clutch Clearance
Also, check out www.tcraonline.
com for additional updates, speaker bios and pictures from this past
year’s event.
Fo
Items r Sale
Surplus Converter Rebuilding Equipment
Converter Source Inc, equipment for sale
by ATI Performance Products
All equipment was recently taken out of a working
facility and is being stored, ready to load onto your
truck while the company is preparing to relocate and
update equipment. All equipment is being sold in
as-is condition. All equipment was working properly
when power was disconnected. View a list of items
for sale at www.tcraonline.com.
.032” to .044”
Application:
Common malfunction:
2000 and newer Ford Escape with 3.0L engine
Cracked clutch piston
Degree of rebuild difficulty:
Largest area of concern:
6
Careful clutch inspection
Mark Mustard responds to: Why should I join the TCRA?
I
would like to take a minute of your time to tell you why
I have been a member of TCRA for eight plus years.
Number one and foremost: the seminars. Every one I
have been to I feel like I have learned something that,
to me, paid for the trip. There is so much information to
learn, and you can get it there by talking to others in the
industry and listening to the speakers from GM, Chrysler
and Ford. The hands-on tours help you learn what other
people are using, including equipment, gasses to check
Gold Sponsors:
Contact J.C. Beattie
1(800) 284-3433
TCRA thanks all gold and platinum sponsors!
Mark Mustard, Branting Industries
303-941-2629
Torque Converter Rebuilders Association
4615 Aircenter Circle
Reno, Nevada 89502
E-mail: [email protected]
for run out, how they cut a captive clutch, etc. You can
get all this, and more. Number two: the newsletters. You
get one every month with membership, and they include
different topics about torque converters with ads for
equipment and sponsors. Three: the web site. You also
have access to TCRA online were you can get so much
more information. Since it is updated weekly, we are
looking into having a question forum were you can ask
questions that will be sent to all the board members.
With such ease, we will be able to e-mail or phone to
help you. We are also looking into putting up videos
that might be helpful to the industry. I hope this will
be helpful in making your decision to becoming TCRA‘s
100th member. If you have any questions, I, or one of
the board members, would be happy to help you.