TM 5-3810-300-24 & P2
Air Oil Cooler.
Mounted in front of the radiator is an air oil cooler. The air oil cooler cools the oil used by the Superstructure Systems.
The cooler is mounted forward of the radiator. Air drawn across the radiator by the engine fan flows across the air-oil
cooler and cools the oil returning to the Superstructure hydraulic oil reservoir.
The transmission used is the RTO613T. The transmission has 13 forward speeds and 3 reverse speeds.
These units consist of a 5 speed front section and a 3 range auxiliary section.
Rotors in the front section are used once through intermediate range of the auxiliary and once through direct range. This
provides a simple repeat shift pattern.
A transmission countershaft brake is mounted on the gear shift. When the countershaft brake button and the clutch are
depressed air flows to the countershaft brake in the transmission. This locks the countershaft assemblies and the main
shaft stops turning. This braking device should be used when the Carrier is standing still.
All speeds are controlled with one lever. The range selection is made with a 3-position selector valve mounted on top of
the gear shift lever.
When in "low" and "intermediate" the control valve shuts off the air supply to the end cap. Thus, the constant air entering
at the constant supply port forces the piston to the rear. The constant air also flows through a channel in the center of the
piston and to an external port which is aligned with the low range port of the air valve.
When in "direct" the control valve opens and supplies air to the end cap. Since the piston area is larger on this end of the
piston, it is forced in the opposite direction. The exhaust air port in the piston is now aligned with the direct range port of
the air valve.
The twin countershaft design, splits torque evenly between two countershafts, reducing gear tooth pressure and wear.
The floating main shaft gears of this design eliminate gear bushings and sleeves as gears "float" between mating gears
on the countershafts.
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