MAINTENANCE OF M939 SERIES VEHICLES - OD1661 - LESSON 1/TASK 2
red clip lead of W2 to the wire removed from the sending unit. The
black clip lead is connected to any good ground. Now he places the
vehicle accessory switch in the ON position. Since the VTM indicated
the proper battery voltage, SGT Bowers is directed to replace the
temperature sending unit.
The procedures for replacing the
temperature sending unit are contained in paragraph 4-60 of
After the temperature sending unit has been replaced, SGT Bowers
repeats the test procedures to ensure that the malfunction has been
corrected and that no additional malfunctions exist.
paragraphs we will follow SGT Fox as she troubleshoots the
transmission for the malfunction TRANSMISSION OVERHEATS (ACCORDING TO
TRANSMISSION TEMPERATURE GAGE) and reaches the conclusion that the
transmission temperature gage is defective and needs to be replaced.
Before beginning the troubleshooting procedure SGT Fox reads DA Form
2404 and talks with the operator. After this has been done SGT Fox
reads through the troubleshooting procedures to determine what tools
will be necessary for this troubleshooting procedure.
malfunction she will need only a mechanic's general toolbox.
the tools have been gathered together, she configures the vehicle
according to the procedures contained in paragraphs 3a(1) thru 3a(5)
on page 34 of this task. Once the tools have been gathered together
and the vehicle is safely configured, SGT Fox is ready to begin
Step 1. First, she checks the transmission oil level. Finding this
adequate, according to LO 9-2320--272-12, SGT Fox moves on to step 2.
In this step she is directed to test the operation of the
transmission temperature gage, using a gage that is known to be good.
Since the test gage did not indicate overheating, the old gage is
defective and should be replaced following the procedures contained
in paragraph 4-53 of TM 9-2320-272-20-1.
Transfer Case System Troubleshooting. In the following paragraphs
we will follow SGT Mitchell as he troubleshoots the transfer case for the