Chevrolet 10 Series 1968, Service Manual, Page: 507 / 713

CLUTCHES AND TRANSMISSIONS 7-44
remain in second until the vehicle speed or the
throttle are changed to obtain first gear operation
in the same manner as in D Range.
L I. - L I Range can be selected at any vehicle speed,
and the transmission will shift to second gear and
remain in second until vehicle speed is reduced to
approximately 40 MPH, depending on axle ratio.
L I Range position prevents the transmission from
shifting out of first gear.
It is very important that any communication concerning
the Turbo Hydra-Matic always contain the transmission
serial and vehicle identification number and that all
transmission parts returned to Chevrolet Motor Division
always be tagged with the transmission serial number.
MAINTENANCE AND ADJUSTMENTS
TRANSMISSION FLUID
Transmission fluid level should be checked with trans­
mission warm and selector lever in “ P” Park position
(“ N” Neutral position on 30 Series Trucks), every time
engine oil level is checked or as specified in Section 0
when engine oil is changed.
CA U TIO N : Since the Turbo Hydra-Matic trans­
mission is very sensitive to oil level, special
precautions should be taken when checking the
oil level, to insure against an overfill.
Transmission fluid should be changed as specified in
Section 0.
Fluid Checking Procedure
C A U TIO N :
The full mark on the dip stick is
an indication of transmission fluid at normal
operating temperature of 180°F. This tempera­
ture is only obtained after at least 15 miles of
expressway driving or equivalent of city driving.
1. With manual control lever Park position start engine.
DO NOT RACE ENGINE. Move manual control lever
through each range.
2. Immediately check fluid level with selector lever in
Park, engine running, and vehicle on LEVEL surface.
At this point, when a reading is made, fluid level
on the dip stick should be at the “ FULL” mark.
3. If additional fluid is required, add fluid to the
“ FULL” mark on the dip stick.
If vehicle is not driven 15 expressway miles or
equivalent, and it becomes necessary to check fluid level,
the transmission fluid must be at room temperature
(70°F.).
With fluid at room temperature (70°F.) follow Steps 1,
2 and 3 below.
1. With manual control lever Park position start engine.
DO NOT RACE ENGINE. Move manual control lever
through each range.
2. Immediately check fluid level with selector lever in
Park, engine running, and vehicle on LEVEL surface.
At this point, when a reading is made, fluid level
on the dip stick should be 1/4" below the “ ADD”
mark.
3. If additional fluid is required add fluid to bring level
to 1/4" below the “ ADD” mark on the dip stick.
CA U TIO N : Do Not Overfill, as foaming and
loss of fluid through the vent pipe might occur
as fluid heats up. If fluid is too low, especially
VIEW B
F ig . I T —Control Linkage (C A 10-20-30 Models) F ig . 2 T—Upper Control Linkage (PS 2 0 -30 Models)
CHEVROLET TRUCK SERVICE MANUAL