GMC 4000 Series Service Manual page 448

" THROUGH-DETENT" shift points are not cor­
rect, the TV mechanism in the transmission may
be sticking. The " THROUGH-DETENT" position
should not allow transm ission to upshift and
should allow downshifts at highest rpm possible.
CAUTION: The t r a n s m i s s i o n
should not be operated if throttle link­
age is not adjusted correctly because
insufficient TV pressure could cause
reduction of main pressure, which in
turn, might result in clutch slippage
and transm ission failure.
A c c e le r a to r And TV Linkage A djustm ent
Procedure - Gas Engine Models (Refer
to Views A and B, Fig. 5)
1. Apply parking brake firmly. Adjust engine
idle speed to specified rpm in drive (3-6 range),
then stop engine.
2. Disconnect clevis (G) from TV lever (F).
Position lever (A) 0.060 inch from stop (B).
3. With carburetor throttle lever (C) at idle
position and lever (A) 0.060 inch from stop (B),
adjust the swivels on rod (I) to provide free-entry
into levers (A) and (C).
4. With carburetor throttle lever (C) at idle
position, and TV lever
(rotated away from engine), adjust clevis (G) on
rod (H) for free-entry into lever (F). Then turn
clevis (G), to shorten rod, two full turns. Install
clevis pin, tighten jam nut and secure clevis (G)
to TV lever (F) with cotter pin.
NOTE: On tilt cab models, with carburetor
throttle lever (C) in idle position, rod (J) should
clear radiator support by 1/8-inch. Lengthen rod
(J), as necessary.
IMPORTANT: Adjustment of the detent but­
ton (E) is accomplished by loosening jam nut
located at cab floor, rotating detent button to
proper height and then retighten jam nut (see
fig. 5). With the accelerator pedal depressed to
the thru-detent position (detent button (E) - com­
pressed) ample clearance must exist between the
pedal and floor, to assure complete movement of
the TV linkage to the thru-detent position.
5. With the accelerator pedal (D) just touch­
ing detent button (E), the carburetor throttle lever
should be in full throttle position. If adjustment
is required shorten or lengthen rods between
accelerator pedal and carburetor throttle lever
and, if necessary, reposition detent button (E) to
obtain above conditions.
6. Using a tachometer to accurately check
engine rpm, road test or dynamometer test vehi­
cle to check for full throttle, full load upshift (5th
to 6th). Upshift should occur at approximately
G M C S E R V I C E M A N U A L
(F) against rear stop
TRANSMISSION CONTROL LINKAGE
50 rpm below the engine governed speed. If up­
shifts do not occur at specified rpm, adjust as
follows:
a. To raise shift point, shorten rod (H), by
turning clevis (G) one turn at a time until the
desired shift point is obtained. Tighten jam nut
securely against clevis.
b. To lower shift point, lengthen rod (H) by
turning clevis (G) off rod one turn at a time until
the desired shift point is obtained. Tighten jam
nut against clevis.
Accelerator And TV Linkage Adjustment
Procedure - Toro-Flow Equipped Models
(Refer to View C, Fig. 5)
1. Start engine and adjust idle speed to spe­
cified rpm, then stop engine.
2. Disconnect clevis (G) from TV lever (F).
Position lever (B) 0.060 inch from stop (C).
3. With injection pump control lever (A) at
idle position and lever (B) 0.060 inch from stop
(C), adjust the swivels on rod (I) to provide free-
entry into levers (A) and (B).
4. With injection pump control lever (A) at
idle position, and TV lever (F) against rear stop
(rotated away from engine), adjust clevis (G) on
rod (H) for free-entry into lever (F). Then turn
clevis (G), to shorten rod, two full turns. Install
clevis pin, tighten jam nut and secure clevis (G)
to TV lever (F) with cotter pin.
IMPORTANT: Adjustment of the detent but­
ton (E) is accomplished by loosening jam nut
located at cab floor, rotating detent button to
proper height and then retighten jam nut (see
fig. 5). With the accelerator pedal depressed to
the thru-detent position (detent button (E) - com­
pressed) ample clearance must exist between the
pedal and floor, to assure complete movement
of the TV linkage to the thru-detent position.
5. With the accelerator pedal (D) just touch­
ing detent button (E), the injection pump control
lever should be in full throttle position. If adjust­
ment is required shorten or lengthen rods between
accelerator pedal and injection pump throttle
lever and, if necessary, reposition detent button
(E) to obtain above conditions.
6. Using a tachometer to accurately check
engine rpm, road test or dynamometer test vehi­
cle to check for full throttle, full load upshift (5th
to 6th). Upshift should occur at approximately
50 rpm below the engine governed speed. If up­
shifts do not occur, adjust as follows:
a. To raise shift point, shorten rod (H), by
turning clevis (G) one turn at a time until the
desired shift point is obtained. Tighten jam nut.
b. To lower shift point, lengthen rod (H) by
turning clevis (G) off rod one turn at a time until
desired shift point is obtained. Tighten jam nut.
Sec. 7A
Page 437