1.
With the engine shut down, use any oil-free or
nonpetroleum-based high-heat lubricant, and
spray or coat a sufficient amount on the restricter
valve shaft and the attaching locations at each
end of the actuation cylinder. See
Fig. 7.20
.
2.
With your hands or a pair of pliers, motion the
valve several times to distribute the lubricant
down the shaft and the attaching locations.
NOTE: Starting the engine and idling for short
periods of time is not recommended. During a
cold engine start-up, enough moisture is devel-
oped within the engine and the exhaust system
to create a corrosion hazard that could affect
the future operation of the Pacbrake. The brake
housing may trap water in the valve shaft bore
causing corrosion in an improperly functioning
or nonfunctioning brake. If it is necessary to pe-
riodically start the engine, it is recommended
that normal operating temperatures be attained
before shutting down the engine.
Allison World Transmission
Pacbrake exhaust brakes on engines that are used
with the Allison World Transmission MD series, are
interfaced with the transmission electronic control
module (ECM). An exhaust-brake-enabled transmis-
sion ECM will usually provide converter lockup in
gears two through six. Effective exhaust braking be-
gins when the transmission automatically downshifts
into fifth gear (62 mph or less). Once on, the
Pacbrake exhaust brake will control road speed
and/or slow the vehicle sufficiently that the transmis-
sion will automatically downshift, if necessary, to Alli-
son’s preselect mode.
The preselect mode is normally assigned to second
gear; however, the transmission can be repro-
grammed by an Allison Transmission Distributor to
third or fourth gear, should the operator desire. If ad-
ditional retarding power is required before the auto-
matic downshifting occurs, you can select a lower
transmission gear on the Allison shift selector.
03/06/2000
f490228
A
A
A
A. Lubrication Point
Fig. 7.20, Pacbrake Exhaust Brake and Air Cylinder
Engines
7.18
