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78-1 2
1977 PONTIAC SERVICE MANUAL
2. Disengage the clutch, wait nine seconds and shift the
transmission to reverse. No grinding noise should be heard.
A grinding noise indicates incorrect clutch adjustment, lost
motion clutch misalignment or internal problems such as
failed dampers, facings, cushion springs, diaphragm spring
fingers, pressure plate drive straps, etc.
SHIFT LINKAGE ADJUSTMENT
A. Column Shift Control
1. Remove the shift control rods from the column levers.
2. Check shift effort at the shift control lever knob (effort
should not exceed 2 lbs. with transmission linkage removed).
3. If binding is felt, refer to the adjustment procedure
for the steering column lower bearing for Manual
Transmission Column Shift as described in the Steering
Section of the Pontiac Service Manual.
4. Lubricate all rod and swivel connectors and recheck
shift effort after installation.
5. If shift linkage is free from binding, the column levers
should be checked for end play. A .005" feeler gage should
fit between the levers and control lever.
6. Connect control rods and check steering column
control levers for alignment. In neutral, the column control
lever tangs should line up with the slot in the main control
lever.
B. Floor Shift Control
1. The cross-over from first-second to the third-fourth
position on four-speed transmissions and from reverse-first
to the second-third position on three-speed transmissions
should be smooth without any offset or step.
2. All swivels, rods and mountings should be checked
for lost motion and repaired or replaced as necessary.
Transmission control levers should be checked for wear and
repaired or replaced as necessary.
TRANSMISSION SHIFT EFFORT
A. Transmission Shift Effort Checking
Procedures
1. Remove the shift rods at the transmission and align
the sleeve, blocker ring and gear by shifting into the offending
gear and then back into neutral.
2. Check the torque required to shift into gear with an
pound inch torque wrench on the shift lever attaching bolt.
If more than the specified torque (see below) is required, the
transmission shift lever should be checked for rust or dirt
binding the lever.
3. Clean levers, lubricate and recheck the torque value.
NOTE: If, at this point in the procedure, it is found that
high shift effort or gear clashing still exists, an anti-
chatter lubricant (positraction additive) should be used.
The lubricant is available in a 4 oz. plastic bottle and can
be squirted into the transmission through the filler plug.
I
SHIFT
BSPEED
4-SPEED
4SPEED
EFFORT
I
76mm
I
76mm
1
82mm
I
Fig.
78-9
Shift Effort
-
Pound lnches
LB. IN.
B. Transmission Internal Problems Related to
Shift Effort
When the above procedures have been checked and the
problem still exists, the transmission will have to be removed
and disassembled for further diagnosis. There are three basic
types of transmission internal problems reflected by shifting
effort.
1. Hard Shifting
-
The effort to shift is excessive, but the
gears engage. The lever moves with excessive effort
throughout the entire travel range. If the static shift effort is
high (clutch depressed, engine not running), the synchronizer
sleeve and hubs should be checked for a tight fit. With the
three synchronizer keys removed, the sleeve should be loose
on the hub. If the hub and sleeve are not a loose fit, replace
the synchronizer assembly.
2. Blockout
-
The lever moves freely until the
synchronizer is engaged. Synchronization should be heard to
take place, but the gear will not engage. When it does engage,
a double bump is generally felt in the lever.
The synchronized blocker ring can be damaged by
excessive force on gear cones that are finished improperly.
The blocker ring material may stick to the synchronizer gear
cone, causing it to be a yellowish brass color, in streaks, which
results in hard shifts when present. The gear cone should be
a bright silver color. Polish the gear cone with 400 grit paper
to a bright silver when this condition is present. The blocker
rings should be replaced if the thread is damaged or worn.
3. Clash
-
Gear clash is a typical sound which occurs
when the sleeve and gear chamfers contact each other in the
unsynchronized state. The characteristics of clash are a
grating or loud buzzing sound from the transmission. The
shift lever load will be lower, but a vibration should be felt.
The noise (clash) can be for a short instant or long enough
to keep the gear from being engaged. This condition should
not be confused with hard shifting or reported as such. Hard
shifting and clash are directly opposite conditions. When the
clash is slight, the load will build up on the shift lever and
then fall off rapidly followed by the grating sound.
If the transmission has been clashing, the sleeve ends
should be examined for chipping and burrs. If the sleeves are
damaged, the synchronizer assemblies and blocker rings
should be replaced. Synchronizer sleeve ends should have an
angular surface. The surfaces should be even from side to side
and the radii indicated should be very small. Any chipping
will require synchronizer replacement.
Check the synchronizer load. When the keys are
installed, the spring ends on one side of the hub should be
hooked in one key and the spring on the opposite side of the
synchronizer should not be hooked on the same key. A
definite load should be felt when the sleeve is moved on the
hubs with the keys and springs in proper position.
501 6
50
80
92
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