Chevrolet 70 Series 1970, Service Manual

Page: 629 / 841

TRANSMISSIONS AND CLUTCHES 7-30
in d icates that the air valve i s defective, or that
actuating p a rts in shifting bar housing a re jam m ed
or defective.
Check Point "D"
1. P u ll the control button up to high range and
d iscon n ect the low range a ir lin e, either at fitting
on the sh ift cylinder or at sid e port of a ir v a lv e.
2. Repeat p roced u res under Check Point "C,"
r e v e r sin g the position of the control button in order
to check low range operation.
Check P oint ”E’’ (R efer to F ig. 15)
If any of the s e a ls in the range shift cylinder
a r e d efectiv e, the range sh ift w ill be affected . The
d eg ree of lo s t a ir w ill govern the degree of fa ilu re,
fro m slow shift to com p lete fa ilu re.
1. Leakage at s e a l "A" or "B" r e su lts in fa il­
u re to sh ift into eith er low or high range; steady
lea k out a ir valve breather in both ranges.
2. Leakage at s e a l "C" r e su lts in fa ilu re to
sh ift into low range; p r e ssu r iz in g of tr a n sm issio n .
.G R EEN LINE (INLET)
■ RED LINE (OUTLET)
T-6665
yRED LINE
BLACK LINE
G REEN LINE
SPLITTER GEAR AIR SYSTEM (RT0913)
(R efer to F ig s. 9 and 10)
A ir Supply
1. Check lin e s for lea k s.
2. Check lin e s to s e e that they a r e not blocked
due to crim ped lin e s.
3. With norm al v e h icle a ir p r e ssu r e , d iscon ­
nect ]i" a ir lin e at sid e port of sp litte r cylinder
co v er. T here should be a steady flow of a ir at a ll
tim e s. If a ir gauge is availab le, take p r e ssu r e
reading which should be 57 to 62 p s i.
4. R em ove the 1/8" O.D. a ir lin e at the supply
port of the sp litte r control. T here should be a con­
stant flow of a ir from th is lin e at a ll t im e s .
S p litter Control Valve
1. With the sp litter control in the "DIRECT"
p o sitio n , disconnect the 1/8" O.D. red a ir lin e
from the center port of the sp litte r cylin d er cover.
T here should be no a ir on th is lin e .
2. Move the sp litte r control to the "OVER­
DRIVE" position; th ere should now be a ste a d y flo w
o f a ir from th is lin e. A ir flow w ill stop when sp lit­
te r control is m oved to the "DIRECT" p osition.
NOTE: If the above r e su lts a re not obtained,
th is in d ica tes a faulty sp litte r control v a lv e. Cause
can be d efective p a rts, damaged O -rin g, lo o s e top
p late sc r e w or blocked a ir lin e .
3. Any stead y flow of a ir from the sp litte r
control valve exhaust port indicates a faulty sp litter
control valve o r in co rrect hook-up. C ause can be
d efective p a r ts, dam aged O -rin g, lo o s e top plate
sc r e w o r r e v e r se d a ir lin e s on control.
RETAINING
NUT
GASKET
AIR INLET FILTER ELEMENT
Figure I0 —RT0 913 Air Controls (Tilt Cab Models)
Figure 11 —Fuller Transmission Air Filter
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCl>. SHOP MANUAL