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GM COACH MAINTENANCE MANUAL
Sec. 17
Page 189
1. Install mainshaft center bearing retainer
in counterbore at rear of main case. With angle
drive case attaching studs in place, place angle
drive case on main case and install stud nuts.
Tighten stud nuts evenly and firmly to draw the
cases together.
Mainshaft center bearing retain-
er will act as a pilot to assure correct position
of angle drive case on main case.
2. Using a drill slightly smaller than over-
size dowel pin diameter, enlarge the dowel pin
holes.
Then ream dowel pin holes to size given
in "Specifieations" at end of this section.
3.
Remove stud nuts and separate the two
cases; then add counterbore in angle drive case
to accommodate oversize dowel pin snap rings (8,
fig. 8).
4.
Press or drive oversize dowel pins into
holes in main case with snap rings contacting
surface of case.
ANGLE DRIVE CASE COVER INSTALLATION
(Fig. 1)
Accomplish the following operations in the
event that new angle drive case is to be installed
with original angle drive case cover or vice versa.
Perform operations which follow with transmission
drive gear and mainshaft installed in main case
and the angle drive case assembled on main case.
1. Press mainshaft rear bearings (30 and 33)
into retainer (31) then bolt bearing and retainer
assembly and cap {36) onto angle drive case cover.
2. Install angle drive case cover on angle
drive case, guiding rear bearing over rear end
of mainshaft to locate cover on case. Strike angle
drive case cover with soft faced hammer to seat
cover against angle drive case then install stud
nuts finger tight. Rotate mainshaft to insure pos-
itive alignment of cover with mainshaft,
then
tighten cover retaining nuts.
3.
Using a drill slightly smaller than standard
dowel pin diameter (refer to "Specifications") drill
new dowel pin holes through pin boss in cover and
into angle drive case to depth of at least 1 inch,
being careful to avoid original holes.
4.
Line ream new holes to .6525 to .6550
inch then remove cover and enlarge holes in cover
to .6565 to .6570 inch.
5.
Remove angle drive case cover and press
or drive oversize dowel pins into new holes in
angle drive case.
CLUTCH HOUSING (Fig. 1)
If
clutch housing is replaced with new part,
ream dowel pin holes in new part to size listed
in "Specifications" at end of this section, using
bearing cap (86) installed on main case as a pilot
for locating clutch housing.
TRANSMISSION
TRANSMISSION SUBASSEMBLY
BUILD-UP
Procedures as outlined in following paragraphs
should be followed in order to assemble trans-
mission with minimum time and effort.
ASSEMBLING COUNTERSHAFT & GEARS
(Fig.
1)
1.
Press third speed countershaft gear (69)
on shaft. Make certain that both keys are in po-
sition and keyways are free from burrs.
2.
Place spacer (72) and keys (73) in position
and press drive gear
(71)
into place.
3. Install drive gear retaining washer (74)
with recessed edge towards bearing (75).
4. Install front bearing inner race (75), re-
taining washer ( 7 6) and nut (77).
Tighten nut se-
curely and install cotter pin.
5. Install front bearing (75) into case if it has
been removed.
6. Install sliding clutch
(63)
over countershaft
clutch gear (
62).
Do not install first speed gear
(61) at this time.
MAINSHAFT AND DRIVE GEAR ASSEMBLY
(Fig. 1)
1. Place mainshaft in vise with rear end of
shaft down (vise should be equipped with "soft"
jaws).
2. Make sure second speed gear (101) is thor-
oughly clean especially on inside diameter then
apply a coat of heavy gear oil.
Place gear over
mainshaft in position shown in figure 1.
3. Install 69 roller bearings (107) in hub of
gear. Install bearing spacer (108) and push bear-
ings and spacer in position. Then install top row
of roller bearings.
4. Install third speed gear thrust collar (106)
and install third speed gear (97) and bearings (94)
in same manner as second speed gear. There are
69 roller bearings used in each row.
5. Install third and fourth speed clutch gear
(93) over splines of main shaft.
Install sliding
clutch (78) over gear (93).
6.
Install washer (92) and retaining nut (80)
and tighten firmly.
7.
Lock nut with lock washer.
8. Reverse position of shaft in vise and in-
stall first and second speed sliding clutch (103).
9. Install first gear (9) over mainshaft, in-
serting roller bearings (110) and spacer (111) in
same manner as second and third speed gears.
10. Remove mainshaft with gears from vise.
11. Coat inner face of thrust washer (112)
with grease and place in position.
Grease will
prevent washer from sliding out of place when
assembly is lowered into case and in that manner
prevent bearings from falling out when shaft is
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