PS Magazine - TB 43-PS-574
PS, The Preventative Maintenance Monthly
ISSUE 574
SEPTEMBER 2000
PS 574
8
SEP 00
HEMTT Tankers . . .
Check for V5 Valve Interference
N
ext time you mechanics have the right-side access cover off your M978-
series HEMTT tanker, eyeball the V5 flow valve air actuator and the 90
°
pipe
elbow just above it.
If the two components are touching or if you see wear marks on the pipe
where they’ve rubbed against each other, your tanker is NMC until repairs are
made.
The rubbing eventually will put a hole in the elbow, creating a fire hazard and
spilling fuel on the ground.
Repair procedures to fix this prob-
lem, which first surfaced in the early
’90s, are in TACOM Safety-of-Use
Message (SOUM) 94-07. Contact
your local TACOM logistics assis-
tance representative for a copy.
If that doesn’t work, let Half-Mast
know. Give him an address and he’ll
send a copy by mail.
perators of some PLS tractors are report-
ing problems with transmission DO NOT
SHIFT lights or transmissions that won’t shift.
Alternator voltage peaks are a possible cause.
M1074/M1075 PLS . . .
2.
Start the engine. (Don’t op-
erate the truck for too long with
the regulator disconnected or
you’ll run down the battery.)
3.
Check to see if the DO NOT
SHIFT light goes out. If it does,
the alternator is the problem
and there’s a capacitor installa-
tion kit available to fix it.
Contact the Oshkosh Truck
Defense Service Department,
(800) 235-9151, Ext 2681, to get
the free kit.
All tractors with 200-amp alterna-
tors installed after Jun 99 and with
serial numbers 66376 and higher have
the capacitor already installed. The
alternators have serial numbers 318
and higher.
If the DO NOT SHIFT light stays
on when the truck is started with
the voltage regulator disconnected,
the alternator is not the problem.
Continue to troubleshoot.
Some PLS tractors, built between Aug 97
and Jun 99 with serial numbers 63479 through
66375, are experiencing voltage peaks on the
200-amp alternator. The peaks show up as
DO NOT SHIFT lights on the dashboard, or
even as a transmission that won’t shift after
the engine is started.
Here’s an easy check mechanics can use to
determine if the alternator is the problem:
1.
Disconnect the electrical connector from
the voltage regulator mounted on the
alternator.
PS 574
9
SEP 00
Disconnect regulator connector from alternator
DO NOT SHIFT lamp lighting?
Check for rub
marks between V5
valve and elbow
i turned
the light on
to let him know
to check my
alternator!
PS 574
8
SEP 00
what the.
..?
the
do not shift
light just
came on!
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