Chevrolet 2003 Corvette Owner's Manual page 86

If your engine speed drops below 900 rpm, or if the
engine is not running smoothly, you should downshift to
the next lower gear. You may have to downshift two
or more gears to keep the engine running smoothly or
for good engine performance.
Notice: When you are shifting gears, don't
move the gearshift lever around needlessly. This
can damage parts of the transmission and may
require costly repair. Shift directly into the next
appropriate gear.
One to Four Shift Light
(Manual Transmission)
1 T O 4
SHIFT
When this light comes on,
you can only shift from
FIRST (1) to FOURTH (4)
instead of FIRST (1) to
SECOND (2).
You must complete the shift into FOURTH (4) to turn
off
this feature. This helps you get the best possible fuel
economy.
After shifting to FOURTH (4), you may downshift to a
lower gear if you prefer.
Notice: Do not try to force the shift lever into
SECOND (2) or THIRD
(3)
when the 1 TO 4 SHIFT light
comes on. Do not try to re-engage FIRST (1) after
starting to shift into FOURTH (4). You will damage
your transmission. Shift only from FIRST (1) to
FOURTH (4) when the light comes on.
This light will come
on
when:
e
The engine coolant temperature is higher than
e
you are going 15 to 19 mph (24 to 31 km/h) and
169°F (76"C),
you are 21 percent throttle or less.
Downshifting (Manual Transmission)
If your vehicle is a coupe or convertible, do not downshift
into the gear shown below at a speed greater than
shown in the table:
2-29