Engine Brakes And Cruise Control; Shifting - Detroit Diesel MBE 900 Operator's Manual

Use Cruise Control after down shifting
on a hill to pull the hill. Hitting the
RSM/ACL Switch (not the Set Switch)
will keep the truck accelerating in the
lower gears up to the rated engine
speed.
Cruise Control will disengage below
1000 rpm or 32 kph (20 mph) road
speed. When using Cruise Control,
if you want to pull the engine below
1000 rpm, remember to hold the
throttle pedal to the floor to keep the
engine pulling at wide-open throttle.
Realistically, the engine will pull to
about 1050 rpm.
Remember: The electronic data
programmed into the DDEC VI
system will not allow you to hurt or
overfuel the engine at low or "lug"
engine speeds. There is enough oil
pressure to withstand hard pulls at low
engine speeds.
Engine Brakes and Cruise
Control
If your engine is equipped with both
Cruise Control and engine brake
retarders, the engine retarders can
operate automatically while you
are in Cruise Control. If the Cruise
Control/Engine Brake function is
turned ON in the MCM programming,
the engine retarders will come on
"low" when your set road speed
increases a few miles-per-hour
(kilometers per hour) above your
All information subject to change without notice. (Rev. 04/08)
DDC-SVC-MAN-0040 0704 Copyright © 2008 DETROIT DIESEL CORPORATION
MBE 900 ENGINE 2007 OPERATOR'S GUIDE
cruise set speed. If your speed
continues to increase, the MCM will
increase the engine retarders' braking
power progressively. When the
vehicle returns to the set cruise speed,
the engine retarders will turn off until
you need them.
For safety reasons, don't use Cruise
Control when it is not possible to keep
the vehicle at constant speed due to:
□ Winding roads
□ Heavy traffic
□ Slippery pavement
□ Descending grades that call for
engine brake assistance.
For an explanation of the engine brake
retarder system and recommendations
for proper operation, refer to ENGINE
BRAKE SYSTEM.

Shifting

Depending on your transmission
model, the gear split may vary from
500 to 300 rpm. The electronic
governor provides almost no overrun
capability; and, if the transmission
is downshifted too early, you will
experience a temporary loss of pulling
power until the engine speed falls
below rated speed.
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