GMC 2003 GMT560 T-Series, Owner'S Manual

Page: 55 / 284

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
rotation so that FIRST (1) or REVERSE (R) 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 REVERSE (R). 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 FIRST (1) or
REVERSE (R) gear.
Notice: After engaging FIRST (1) or REVERSE (R)
gear, do not use the clutch brake for upshifting
and downshifting. To do so will shorten the service
life of the clutch brake and gear selection shift
efforts may be increased.
Parking
{
CAUTION:
If you don’t park your vehicle properly, it can
roll. If you’ve left the engine running, it can
move very quickly. You or others could be
injured. To be sure your vehicle won’t move,
even when you’re on level ground, follow the
steps below.
Two-Speed Rear Axle
1. With the engine running, shift the two-speed rear
axle into low. To be sure it’s in low, you’ll need to
move the vehicle in gear just a little.
2. Hold the regular brake pedal down with your
right foot.
3. Apply the parking brake.
4. Shift the transmission to NEUTRAL or PARK (P).
2-19