Range Inhibit Warning Indicator - GMC 2003 GMT560 T-Series Owner's Manual

Service Transmission Warning Light
If your vehicle has an Allison automatic transmission,
certain transmission malfunctions will turn this light on.
If this light comes on while you are driving, do not use
the transmission shift control. Using the transmission
shift control may result in the loss of forward gears. The
computer for the transmission senses a problem and
chooses a gear to stay in so that you can drive the
vehicle in that gear. You may not be able to drive as fast
or back up when this light is on.
This light is located with
the auxiliary warning lights
in the center of the
instrument panel.
Notice: If the service transmission warning light
comes on while you are driving, it is a warning that
making a transmission "range" change could
leave you stranded. The vehicle may not continue to
move if you change gears with the transmission
shift control. The transmission can't operate in all
gears because something is wrong. Leave the
shift control alone, and drive directly to a GM dealer
for service. If you can't go in for service
immediately, have the vehicle towed.

Range Inhibit Warning Indicator

If your vehicle is equipped with an Allison
1000/2000/2400 series automatic transmission, a lighted
bar under the current gear selected will flash.
If your vehicle is equipped with an Allison MD automatic
transmission, the current gear selected on the
pushbutton display will flash.
The flashing bar or gear selection indicates that
transmission range shifts may not occur.
For detailed information on shift inhibit limitations, see
the Allison Automatic Transmission Operator's Manual in
your vehicle for further information.
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