Manual Transmission Diagnosis - Pontiac TRANS AM 1977 Service Manual

MANUAL TRANSMISSIONS 7B-13
MANUAL TRANSMISSION DIAGNOSIS
CONDITION PROBABLE
CAUSE
CORRECTION
Slips Out of High Gear
a. Transmission loose a. Tighten mounting bolts
on clutch housing
b. Shift rods interfere b. Replace or bend levers
with engine mounts or and rods to eliminate
clutch throw-out lever interference
c. Shift linkage does not c. Adjust and free up shift
work freely; binds linkage
d. Damaged mainshaft pilot
d. Replace pilot bearing
bearing
e. Main drive gear e. Tighten or replace main
retainer broken or loose drive gear
f. Dirt between trans- f. Clean mating surfaces
mission case and clutch
housing
g. Misalignment of trans- g. Refer to TRANSMISSION
mission ALIGNMENT
h. Stiff shift lever seal h. Replace seal
i. Pilot bearing loose in i. See Section 6 for
crankshaft bearing fits
j. Worn or improperly j. Adjust or replace
adjusted linkage linkage as required
Noisy in All Gears a. Insufficient lubricant
b. Worn countergear
bearings
c. Worn or damaged main
drive gear and
countergear
d. Damaged main drive
gear or main shaft
bearings
e. Worn or damaged
countergear antilash plate
f. Shift lever boot
damaged (5-Speed
77mm Trans.)
a. Fill to correct level
b. Replace countergear
bearings and shaft
c. Replace worn or damaged
gears
d. Replace damaged bearings
or main drive gear
e. Replace countergear
f. Replace shift lever boot.
Noisy in High Gear
a. Damaged main drive gear a. Replace damaged bearing
bearing
b. Damaged mainshaft b. Replace damaged bearing
bearing
c. Damaged high speed gear c. Replace synchronizer
synchronizer
d. Damaged fifth speed d. Replace damaged parts.
gear or countergear
(5-Speed 77mm Trans.)
Noisy in Neutral with
Engine Running
a. Damaged main drive a. Replace damaged bearing
gear bearing
b. Damaged or loose b. Replace pilot bearings.
mainshaft pilot bearing
c. Worn or damaged c. Replace countergear or
countergear antilash damper (5-Speed 77mm Trans.)
(damper) plate