Two-Speed Rear Axle Electric Shift Control - GMC 2005 T-Series Owner's Manual

There is an indicator light on the instrument panel
similar to the symbol on the switch, that will come on
when the exhaust brake is active. See Exhaust
Brake Indicator Light on page 3-35 for more information.
When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be
most effective if the gear range selected is the lowest
possible range that does not allow the engine rpm
to exceed 2500 rpm.
If you have an automatic transmission and press this
button, the transmission will downshift to a factory
default setting of fourth gear. To change the default
setting, or for more information on factory default
settings, contact your dealer for assistance.
The accelerator and clutch pedals, on a manual
transmission, must be released in order for the exhaust
brake to engage. The exhaust brake will not function
when cruise control is active, and will automatically shut
off when the anti-lock brake system is active.
Two-Speed Rear Axle Electric Shift
Control
If your vehicle has this feature, you will find a label on
the headliner above the windshield or in another
place near the driver that shows how to use it.
The switch is located on the instrument panel to the
right of the climate controls. See Instrument Panel
Overview on page 3-4 for more information.
United States
When the switch is up, the rear axle is in the high
range. Push it down to get the low range.
The two-speed axle should be in low range when you
park the vehicle. Apply the parking brake, shift to
PARK (P) or NEUTRAL (N) and shut off the engine.
To operate off-road or under a heavy load, shift into low
range when the vehicle is standing still and then
operate the transmission normally.
Canada
2-15