1988 PONTIAC FIERO Service Repair Manual

SECTION 7B
5-SPEED 77MM TRANSM
RPO-M39 MK6 AND MBI
CONTENTS
........................... ................... ............................... General Description 7B-1 Gears ... 7B-12 .......................... .............................................. Diagnosis 7B-2 Front and Rear Bearings ..7B-12 ...................... ................................ On Vehicle Service 7B-3 Synchronizer Blocking Rings .7B-12 .................................................. ........................................... Shift Lever 7B-3 Repairs ,7B-12
......................................... ................... Transmission 7B-3 Synchronizer Keys and Springs .7B- 12
....................... ............... Extension Housing Oil Seal 7B-3 Extension
Oil Seal and/or Bushing .7B-13
Speedometer Driven Gear ......................... 7B-6
Drive Gear Bearing Retainer Oil Seal ............ 7B-14
........................................... .................................. Unit Repair 7B-6 Transmission Cover .7B-14
....................... ....................... Disassembly of Transmission 7B-6 Front Counter Shaft Bearing .7B-15 .............................. ......................... Disassembly of Mainshaft .7B- 10 Assembly of Drive Gear .7B- 16 ............................... ........................ Disassembly of Drive Gear ,7B- 1 1 Assembly of Mainshaft 7B- 16 ............................. ............................ Cleaning and Inspection ,7B-11 Assembly of Transmission 7B-17 ........................................ ............................... Transmission Case .7B-11 Specifications .7B-19
....................... .......... .................... Bearing Rollers and Spacers .7B-11 Special Tools ... .7B-20
GENERAL DESCRIPTION
Manual transmissions are identified by (A) the
number of forward gears and
(B) the measured dis-
tance between centerlines of the mainshaft and the
countergear.
The 5-speed 77mm transmission is a fully syn-
chronized unit with blocker ring synchronizers and a
sliding mesh reverse gear. First and second gears have
three-piece synchronizer rings, consisting of steel
inner and outer cones and
a tapered metal ring that is
lined on both sides with friction material similar to
automatic transmission friction plates. The cones are
independent of the gears and can be replaced sepa-
rately. Third and fourth gear blocker rings are more
conventional in appearance, but are also lined with
friction material. The fifth gear blocker ring is brass.
NOTICE: No lubricant other than Dexron I1
#I051855 or equivalent should be used in this
transmission. Other lubricants or additives may
damage the blocker ring friction material or its
adhesive.
The mainshaft and the countershaft are sup-
ported on tapered roller bearings and must be
shimmed for proper end play. First through fourth
speed mainshaft gears ride on caged roller bearings.
An aluminum transmission case houses the various gears and bearings. The gearshift lever assembly is
floor-mounted and is located on top of the extension
housing. The shift mechanism does not require adjust-
ment and can be serviced independently of the
transmission.

Shift rail binding Check
for mispositioned selector
arm roll pin, loose cover bolts,
worn shift rail bores, worn shift
rail, distorted oil seal, or extension
housing not aligned with case.
Repair as necessary.
Internal bind in transmission Remove,
disassemble and inspect
caused by shift forks, selector transmission. Replace worn or
plates, or synchronizer assemblies damaged components
as necessary.
Incorrect lubricant Drain
and refill transmission.
GEAR CLASH WHEN
Clutch travel incorrect Refcr to clutch \cct~on SHIFTING FROM ONE GEAR TO Lubricant level
low or incorrect Drain
and refill transmission and
check for lubricant leaks if level
was low. Repair as necessary.
Gearshift components, or Remove,
disassemble and inspect
synchronizer assemblies worn transmission. Replace worn or
damaged components as necessary.
TRANSMLSSION Drain and refill transmission. If lubricant level was low, check
for leaks and repair as necessary.
Check and correct bolt torque
as necessary.
Clutch housing bore to
cranksahft pilot Check
alignment and adjust as necessary
Gearshift mechanism, trans- Remove,
disassemble and inspect
mission gears, or bearing
com- transmission. Replace worn or
ponents worn or damaged damaged components
as necessary.
JUMPS OUT OF GEAR Offset
lever plastic insert worn or Remove
gearshift lever and check
for loose offset lever or worn
insert. Repair or replace as
necessary.
Gearshift mechanism, shift Remove,
disassemble and inspect
forks, selector plates, interlock transmission
cover assembly.
plate, selector arm, shift rail, Replace
worn or damaged compo
- springs or shift cover worn or nents as necessary.
Gear teeth worn or tapered, Remove,
disassemble and inspect
synchronizer assemblies worn transmission. Replace worn or
or damaged, excessive end play damaged components
7s necessary.
caused by worn thrust washers
WILL NOT SHIFT
or output shaft gears
INTO
ONE GEAR
Gearshift selector plates, inter-
lock plate, or selector arm, worn, transmission cover assembly.
Repail damaged, or incorrectly assembled or
replace components as necessary.
Synchronizer sleeves or hubs, Remove,
disassemble and inspect
damaged or worn transmission. Replace worn or
LOCKED
IN ONE damaged components.
GEAR - CAN NOT
BE SHIFTED OUT Shift rail(s) worn
or broken, shifter
fork bent or worn
Disassemble transmission. Re
-
Figure '1 Diagnosis

5-SPEED 77MM TRANSMISSION 7B-3
ON-VEHICLE SERVICE
SHlR CONTROL LEVER
Remove or Disconnect
1. Screws from transmission shift lever boot
retainer and slide boot up lever.
2. Shift lever attaching bolts at transmission and
remove lever.
NOTICE: The upper lever is no longer threaded
to the lower lever. The levers are bonded
together. Separation of the levers will damage the
shifter requiring replacement of the shifter
assembly.
Install or Conned
1. Shift lever and attaching bolts to transmission.
2. Shift lever boot, boot retainer and retainer
screws to transmission.
~ibure 2
Remove or Disconnect
1. Negative cable at battery.
2. Shift lever attaching bolts from transmission.
NOTICE: The upper lever is no longer threaded
to the lower lever. The levers are bonded
together. Separation of the levers will damage the
shifter requiring replacement of the shifter
assembly.
3. Raise vehicle.
4. Torque arm. (See Section 3D)
5. Propeller shaft. (See Section 4A)
6. Speedometer cable at transmission.
7. Electrical connection at transmission.
8. Support transmission with suitable jack stand.
9. Transmission mount attaching bolts.
10. Catalytic converter hanger.
Figure 2 Transmission To Engine Attachment
11. Crossmember attaching bolts.
12. Crossmember.
13. Dust cover bolts.
14. Transmission to engine attaching bolts.
15. Transmission.
NOTICE: Inspection of clutch components
should be made after transmission removal. If the
clutch requires repair, see section 7C before
transmission is reinstalled.
Install or Connect
Transmission.
Transmission to engine attaching bolts.
Dust cover bolts.
Crossmember
Crossmember attaching bolts.
Catalytic converter hanger.
Transmission mount attaching bolts.
Remove jack stand supporting transmission.
Electrical connection to transmission. Speedometer cable to transmission.
Propeller shaft. (See Section
4A)
Torque arm. (See Section 3D)
Lower vehicle.
Shift lever attaching bolts to transmission.
Negative cable to battery.
EXTENSlOM HOUSING OIL SEAL
Figure 3
Remove or Disconnect
1 . Raise vehicle.
2. Propeller shaft. (See Section 4A)
3. Pry seal out of extension housing using a
screwdriver.
Figure 3 Extension Housing Oil Seal

5-SPEED 97MM TRANSMISSION 7B-5
1. COVER, TRANSMISSION
50. RACE, FRONT COUNTERSHAFT BEARING
2. BOLT, ALIGNMENT DOWEL
51. BEARING, COUNTERSHAFT
52. GEAR CLUSTER, COUNTERSHAFT
4. SEAL, O-RING
53. RACE, REAR COUNTERSHAFT
5. PLUG, SHIFT
RAIL 54. SHIM, COUNTERSHAFT BEARING ADJUSTMENT
6. RAIL, SHIFT
55. RETAINER, COUNTERSHAFT
7. FORK, 3RD AND 4TH SHIFT
56. BOLT, COUNTERSHAFT RETAINER
8. ARM, SELECTOR
57. GEAR, 5TH SPEED DRIVE
9. PLATE, GEAR SELECT INTERLOCK
58. RING, BLOCKER
- 5TH SYNCHRONIZER
10. FORK,
1ST AND 2ND SHIFT
59. SPRING, 5TH SYNCHRONIZER
11. INSERT, SHIFT FORK
60. HUB, 5TH SYNCHRONIZER
12. PLATE, SHIFT FORK
61. KEY, 5TH SYNCHRONIZER
13. PIN, ROLL
- SELECTOR ARM
62. SLEEVE, 5TH SYNCHRONIZER
14. SHAFT,
MAIN WITH 1ST AND 2ND
63. RETAINER, 5TH SYNCHRONIZER
SYNCHRONIZER HUB
64. RING, SNAP
- 5TH
15. SPRING, SYNCHRONIZER SYNCHRONIZER RETAINER
16. GEAR, REVERSE SLIDING
65. FUNNEL, TRANSMISSION OILING
17. CONE, INNER
- 1ST AND 2ND SYNCHRONIZER
66. PLUG, FILL AND DRAIN
18. CONE, OUTER - 1ST AND 2ND SYNCHRONIZER
67. CASE, TRANSMISSION
19. RING, BLOCKER
- 1ST AND 2ND SYNCHRONIZER
68. SPRING, REVERSE LOCK
20. SLEEVE,
1ST GEAR BEARING
69. O-RING, REVERSE IDLER
21. BEARING,
1ST GEAR
70. GEAR, REVERSE IDLER
22. GEAR,
1ST SPEED 71. PIN, ROLL - REVERSE IDLER
23. BEARING, MAINSHAFT REAR
72. SHAFT, REVERSE IDLER
24. RACE,
MAINSHAFT REAR BEARING
73. FORK, 5TH SHIFT
25. GEAR, 5TH SPEED DRIVEN
74. PIN, ROLL - SHIFT FORK
26. RING, SNAP
75. RAIL, 5TH AND REVERSE SHIFT
27. GEAR, SPEEDOMETER DRIVE
76. RETAINER, SPRING CLIP - 5TH AND
28. CLIP, SPEEDOMETER DRIVE GEAR REVERSE LEVER
29. BEARING,
MAIN DRIVE GEAR THRUST 77.
LEVER, 5TH AND REVERSE SHIFT
30. RACE,
MAIN DRIVE GEAR THRUST BEARING 78. BOLT, 5TH
AND REVERSE
31. RING, BLOCKER
- 3RD AND 4TH SHIFT
LEVER PIVOT
SYNCHRONIZER 79. SWITCH, REVERSE LAMP
32. HUB, 3RD AND 4TH SYNCHRONIZER 80.
CONTROL, TRANSMISSION SHIFT LEVER AND HOUSING
33. KEY, SYNCHRONIZER 81.
SLEEVE, SHIFT LEVER DAMPER
34. SLEEVE, 3RD AND 4TH SYNCHRONIZER 82.
LEVER, OFFSET SHIFT
35. GEAR, 3RD SPEED 83. PIN, ROLL
- OFFSET
LEVER
36. BEARING, 3RD GEAR 84.
SPRING, DETENT
37. SPACER, 3RD GEAR BEARING 85.
BALL, DETENT
38. RING, SNAP 2ND GEAR THRUST WASHER 86.
O-RING, EXTENSION HOUSING VENT
39. WASHER, THRUST
- 2ND GEAR 87. VENT, EXTENSION HOUSING
40. GEAR, 2ND SPEED 88. SEAL, EXTENSION HOUSING REAR OIL
41. BEARING, 2ND GEAR 89. BUSHING, EXTENSION HOUSING
42. SPACER,
2ND GEAR BEARING 90.
HOUSING, EXTENSION
43. RING, SPIRAL RETAINING
- 2ND SYNCHRONIZER 91. BOLT, EXTENSION HOUSING
44. WASHER, THRUST - 2ND SYNCHRONIZER 92.
BOLT, DRIVE GEAR BEARING RETAINER
45. KEY, 1ST-2ND SYNCHRONIZER 93.
RETAINER, DRIVE GEAR BEARING
46. PIN, LOCATING
- 1ST SPEED 94. SEAL, DRIVE GEAR BEARING RETAINER OIL
BEARING SLEEVE
95. SHIM,
MAINSHAFT BEARING ADJUSTMENT
47. SPRING, ANTI-RAlTLE 96. BEARING, FRONT MAIN DRIVE GEAR 48. BALL, ANTI-RATTLE
97. GEAR, MAIN DRIVE
49. O-RING, BEARING RACE
98. ROLLERS, BEARING
- MAIN DRIVE GEAR PILOT
Figure 5 &Speed 99mm Transmission

Install or Conned
1. New seal using Tool J 21426.
2. Propeller shaft. (See Section 4A)
3. Lower vehicle.
4. Check transmission fluid level.
SPEEDOMETER DRIVEN GEAR
Remove or Disconnect
1. Raise vehicle.
2. Speedometer cable.
3. Lock plate and retaining bolt.
4. Pry gear fitting and shaft from housing.
5. O-ring from fitting.
Install or Connecl
1. Coat driven gear shaft and new O-ring with
transmission lubricant.
2. New O-ring.
3. Insert shaft.
4. Position fitting into extension housing.
5. Lock plate and retaining bolt.
6. Speedometer cable.
7. Lower vehicle.
TRANSMISSION
Figure 4
Disassemble
@ Exterior of the transmission assembly
thoroughly with appropriate solvent.
1. Remove drain bolt on transmission case and
drain lubricant.
2. Position offset lever in neutral gate (centered).
NO"6CE: Removal of offset lever in position
other than neutral (centered) may result in driving
the roll pin into the detent plate without releasing
lever, making further disassembly extremely
difficult.
3. Using pin punch and hammer, remove roll pin
attaching offset lever to shift rail (Figure
6).
Figure 6 Offset Lever (Removal and Installation)
4. Extension housing-to-transmission case bolts.
5. Housing and offset lever as an assembly (Figure
7) *
NOTICE: Do not attempt to remove the offset
lever while the extension housing is still bolted in
place. The lever has a positioning lug engaged in
the housing detent plate which prevents moving
the lever far enough for removal.
6. Detent ball and spring from offset lever (Figure
8)
7. Roll pin from extension housing or offset lever.
8. Carefully pry oiling funnel from rear of counter-
shaft (Figure
9).
9. Bolts attaching transmission cover and shift fork
assembly to case.
NOTICE: Two of the transmission cover attach-
ing bolts are alignment-type dowel bolts. Note
the location of these bolts for assembly reference.
10. Cover (Figure 10). I

Figure 7 Extension Housing to Transmission Case Figure 9 Oiling
Funnel
Figure
8 Detent
11. Reverse lever C-clip,pivot bolt and shift lever
(Figure
1 I).
12. Reverse lamp switch.
13. Fifth gear synchronizer snap ring and retainer
from rear of countershaft (Figure
12).
14. Unhook reverse lock spring from front of trans-
mission case (Figure
13). Figure 10 Transmission Cover