PS Magazine - TB 43-PS-587
PS, The Preventative Maintenance Monthly
ISSUE 587
OCTOBER 2001
PS 587
OCT 01
3
PS 587
U
nless your M939-series 5-ton trucks have had MWO 9-2320-272-55-1 applied,
their highway speed limit is still 40 mph.
TACOM Safety-of-Use Message (SOUM) 00-018 (Jul
00),
Resumption of Safe Operating Speeds for M939
Family of Vehicles Following Retrofit of Anti-lock Braking
System (ABS),
authorizes you to resume normal operating
speeds only after MWO 9-2320-272-55-1 is applied.
Application of ABS to your trucks rescinds the require-
ment for MWO 9-2320- 272-20-7 and removes the brake
proportioning valve installed during that modification.
Never add MWO -20-7 to a truck that has been modified
by MWO -55-1. It’s not needed then.
Trucks with the ABS MWO have a yellow
triangular decal with black lettering “ABS” in
the lower left corner of the windshield. ‘Course,
there’ll be a regular MWO tag on the cab rein-
forcement just inside the driver’s door, too.
MWO
9-2320-272-20-7,
which still has not been applied
to some vehicles in the fleet,
installed a brake proportioning
valve kit to prevent front-wheel
lockup during heavy braking
when driving on slick surfaces
with little or no load on-board.
TACOM SOUM 98-07 (Apr
98),
Safe Operating Speeds for
M939 Series Trucks,
dropped
speeds to 40 mph and outlined
safe driver practices. It is still in
effect until MWO -55-1 is
installed.
ABS
MWO
APPLIED
MWO 9-2330-373-55-1
DATE OCT 20 01
Eyeball TACOM Safety-of-Use Message (SOUM) 01-006 (Jan 01), M939
Speedometer NMCS Criteria, for the details.
Since no M939-series truck can be driven faster than 40 mph unless MWO 9-
2320-272-55-1 has been applied, you must have a working speedometer to know
how fast you’re going.
Insert these words
in TM
9-2320-272-10 on Page 2-53
in PMCS Item 19’s “Not Fully
Mission Capable If” column:
SPEEDOMETER
MUST WORK
“Gauges––speedometer/odometer is
inoperative.
Report vehicle immediately
to unit maintenance if speedometer
needle does not move, jerks unevenly
during sustained speeds or appears stuck.”
M939-Series Trucks…
Look for decal
on windshield…
…and MWO plate
on door frame
I
f
your
M939-
series 5-ton truck
has a speedome-
ter that does not
work right or
doesn’t work at
all, your truck is
NMC until it is
repaired or replaced.
075562
OCT 01
Just so
we don’t have
a failure to
communicate…
unless
there’s an
abs decal
on yore wind-
shield, y’all
s’posed to go
40
, and no
faster!
587. 02-03 (C)
9/3/01
6:28 PM
Page 1
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