GMC 2010 T-Series, Owner'S Manual

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Eaton
®
Fuller
®
Nine and Ten-Speed
Non-Synchronized Manual
Transmissions
If the vehicle has one of these non-synchronized
transmissions, it is naturally somewhat complicated.
The following are driving tips:
. Always choose an initial starting gear suitable for
the load and terrain.
. Always use double-clutching procedures when
shifting.
. Never move the range shift lever to the LO speed
gear position after HI range preselection,
or anytime the transmission is in the HI range.
. Never move the range knob or lever with the shift
lever in N (Neutral) while the vehicle is moving.
. Never make a range shift while moving in
R (Reverse).
Double-Clutching
You must use the double-clutching method when you
shift an unsynchronized gear set. Disengage the clutch,
shift to neutral and engage the clutch. When upshifting,
slow the engine until the engine rpm and road speed
match. When downshifting, accelerate the engine until
the engine rpm and road speed match. Then quickly
disengage the clutch and move the shift lever to the
next gear position and engage the clutch.
Clutch Brake (Vehicles with
Non-Synchronized Transmission)
A clutch brake is used to stop transmission input shaft
turning so that 1 (First) or R (Reverse) gear selection
can be initiated when the vehicle is at a standstill and
the engine is idling.
Press the clutch pedal all the way down to the
floorboard to apply the clutch brake.
When using the clutch brake, disengage the clutch
pedal and shift the transmission into either the initial
starting gear or R (Reverse). If the tooth-butting occurs
between the clutching teeth, re-engage the clutch while
applying light pressure to the shift lever. This will
provide for a smooth shift into either 1 (First) or
R (Reverse) gear.
Notice: Using the clutch brake for shifting into any
gear other than 1 (First) or R (Reverse) may cause
premature wear of the clutch brake and make gear
shift effort more difficult. Do not use the clutch
brake for shifting after engaging 1 (First) or
R (Reverse).
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