TM-9-2320-285-10
TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1
TECHNICAL MANUAL; OPERATOR’S MANUAL
JUNE 1985
TM-9-2320-285-10 - Page 10 of 121
TM 9-2320-285-10
1-9.
EQUIPMENT DATA
GENERAL
Ottawa vehicle model .
.......................................
Model 50
Serial numbers .
....................................
55001 thru 55175
Vehicle weight .
.........................................
15,520 pounds
Front .
....................................................
9,740 pounds
Rear .
....................................................
5,780 pounds
Maximum GVW .
................................
43,500 pounds
ENGINE
Make .
......................................................... .
Detroit Diesel
Model .
..............................................................
5067-5340
Design .
.................................................................
6V-53T
Type .
......................................
Overhead 4-Valve, 2-cycle
No. of cylinders .
..............................................................
6
Displacement .
........................................
318 cubic inches
Bore .
............................................................
3.875 inches
Stroke .
.............................................................
4.5 inches
Compression .
........................................................
18.7:1
Brake horsepower .
........................
225 HP @ 2600 RPM
Torque .
.............................................
550 ft/lbs1800 RPM
Governed speed (full load) .
.............................
2600 RPM
Governed speed (no load) .
..............................
2800 RPM
Idle speed .
.........................................................
600 RPM
Firing order .
......................................
1L-3R-3L-2R-2L-1R
Oil capacity (includes 2 quarts required for oil filter
replacement .16 quarts
Oil pressure, hot .
..........................................
40 to 60 PSI
minimum 18 PSI @ 1200 RPM
TRANSMISSION
Make .
...............................................
Detroit Diesel Allison
Model .
....................................................................
MT653
Speeds .
............................................
5 forward, 1 reverse
Governor pressure .
....................
54-58 PSI @ 1500RPM
Main fluid pressure .
........................
125 PSI @ 600 RPM
Fluid temperature .
.............................
160-220 degrees F
Dry weight .
...........................................................
540 lbs.
Gear ratios (mechanical) .
...............................
First 8.05:1
Second 3.58:1
Third 2.09:1
Fourth 1.39:1
Fifth 1.00:1
Reverse 5.67:1
ELECTRICAL
System type .
................................
12 volt negative ground
Batteries .
.......................................
Four 12 volt, lead-acid
Alternator .
...........................................
12 volt, 90 ampere
Starter type .
........................................
Overrunning clutch
FRONT AXLE
Make .
.................................................
Rockwell Standard
Model .
...................................................
FF931-RDAX-72
Capacity .
..................................................
12,000 pounds
Suspension .
....................................
Semi-elliptical spring
Brakes .
........................................................
15 x 5 inches
Tires .
....................................................
12:00 x 20, 16 ply
Inflation pressure .
................................................
120 PSI
REAR AXLE
Make .
.................................................
Rockwell Standard
Model .
..................................................................
PX-149
Type .
......................................................................
U-240
Load rating .
..............................................
31,500 pounds
Suspension .
..............................................
Rubber mount
Reduction ratio.
.................................................... .
11.36:1
Brakes .
..................................................
16-1/2 x 7 inches
Tires
(dual mounted) .
.............................
12:00 x 20, 16 ply
Inflation pressure .
................................................
120 PSI
FIFTH WHEEL
Hydraulic cylinders .
.............................
Two double-acting
Unlatch.
.......................................
Cab control (pneumatic)
Relatch.
.............................................................
Automatic
Lift frame .
...............................................
Fore and aft tilt,
no side tilt
Capacity .
..................................................
70,000 pounds
Lift .
.............................................................
16-3/8 inches
GENERAL CAPACITIES
Cooling system (incl. engine, radiator,
and heaters) .
..............................................
50 quarts
Engine crankcase .
............................................
14 quarts
Transmission
(with new filter) .
...........................................
16 quarts
Fuel tank .
........................................
50 gallons diesel fuel
Power steering system .
.......................................
4 quarts
Hydraulic system .
.............................................
10 gallons
Differential .
...........................................................
38 pints
1-5
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