Chevrolet DB90 Series, Руководство по обслуживанию

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S ec. 7A-151
SECTION 7
ana Clutched
T h is group is divided into s ix sectio n s as shown in Index below:
Section Page No.
7A T ra n sm issio n Control L i n k a g e ............................................................. 151
7B T ran sm ission O n-V ehicle S erv ice O p e r a t io n s ................................ 160
7C A uxiliary T r a n s m i s s i o n s ........................................................................ 164
7D Clutch C o n t r o l s ........................................................................................... 167
7E C lutches ...................................................................................................... 172
7F Front End D rive Pow er Take-O ff ...................................................... 172
SECTION 7A
GantsuU JlinJza^e
A ll inform ation in Heavy Duty Truck Service Manual ST135-70 and ST 332-71 pertaining to
“ TRANSMISSION CONTROL LINKAGE" is applicable to m odels covered by this supplem ent
with addition of the following:
TRUCK MODELS WITH ALLISON MT SERIES AUTOM ATIC TRANSMISSIONS
LINKAGE ADJUSTMENTS
P rio r to making any checks or adjustm ents of
tra n sm issio n manual and throttle control linkage,
check perform ance of the engine. The tran sm ission
is often blam ed for poor operation of the veh icle
when the engine is not tuned to d eliverp eak power.
R efer to GASOLINE ENGINES (SEC. 6A) or 53 AND
71 SERIES DIESEL ENGINES (SEC. 6C) of this
supplem ent for recom m ended tune-up procedures.
It should be kept in mind, that to a ssu r e efficient
perform ance of power plant, the tran sm ission
should be a s carefully balanced with the engine as
a re fu el and ignition sy ste m s.
The tra n sm issio n control linkage must be
checked and properly adjusted whenever any of the
follow ing events occur:
1. At tim e of "New V ehicle Inspection," after
final engine idle adjustm ents have been made.
2. A fter any tra n sm issio n control linkage has
been rem oved or replaced.
3. A fter tra n sm ission has been rem oved and
rein stalled in veh icle.
4. When the tra n sm issio n is not perform ing
properly.
W ARNING
DO NOT STA R T ENGINE WITH SH IFT
LIN K A G E D ISCO N N ECTED , AS SERIOUS
INJURY COULD R E S U L T TO V E H IC L E
OR PER SO N N EL.
ACCELERATOR AND TV LINKAGE
The TV (throttle valve) linkage must be prop­
erly adjusted so that engine and tra n sm issio n , as
a matched p air, can give maximum perform ance.
If tra n sm issio n TV linkage is in correctly adjusted,
the engine may not operate at full governed rpm,
or the tran sm issio n upthift and downshift points
may be in correct.
The TV linkage should be adjusted so that
tra n sm issio n upshift o ccu rs at approxim ately 50
rpm below engine governed speed during full load
operation.
A detent position is incorporated in the TV
linkage to provide additional control of tra n sm is­
sion sh ifts. D E T E N T , referred to a s " fullthrottle”
is the point of full fuel control opening where a c ­
c e lera to r pedal resista n c e is fe lt. TH R U -D ETE N T
is accom plished by d ep ressin g pedal through pedal
re sista n c e until it bottom s.
NOTE: The RM80 and HM80 do not u ti­
liz e a THRU-DETENT type TV linkage. When the
linkage reach es DETENT (full throttle) there is no
additional travel left in the TV linkage. This link­
age is p o ssib le due to the u se of the high-torque
478M engine and MT42 A llison T ran sm ission .
If the DETENT shift points a re co r re ct, but
the THRU-DETENT shift points a r e not correct,
the TV m echanism in the tra n sm issio n may be
stick in g. The THRU-DETENT position should not
allow tra n sm issio n to upshift and should allow
downshifts at the highest rpm p o ssib le.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT