1.
Drain oil
2.
Stand box on end to allow oil to
drain forward
3.
Drain rest of oil
4.
Undo 6 bolts retaining gearlever
extension tower
5.
Remove tower (note it is located
on two dowels)
6.
Undo eight nuts retaining OD unit
(the unit will have to be eased away from the adapter housing to release some of
the nuts
7.
Remove the OD unit
8.
Remove (and carefully store) the
OD pump drive cam and locating ball from the mainshaft
9.
Remove the circlip from the
mainshaft (store with the cam & ball)
10.
Remove the selector interlock
mechanism from the adapter housing
11.
Undo the bolts and nuts holding
the adapter housing to the main case
12.
Remove the adapter housing
13.
Undo the nut retaining the clutch
arm pivot pin and remove pin
14.
Remove the clutch release arm
15.
Undo the front plate nuts
16.
Remove the front plate, retaining
any shims fitted behind the plate (the condition of these shims will tell you if
the input bearing has been rotating in its housing)
17.
Undo the three bolts on the top of
the main case and extract the springs and detent plungers
18.
Undo the bolts holding the side
plate and remove the side plate
19.
Undo the locking bolts on the
selector rods and remove the rods and selectors
20.
Undo the reverse gear locking bolt
(may be tablocked or spring washer)
21.
Withdraw reverse gear shaft from
the rear of the case and remove gear
22.
Measure and note the layshaft end
float
23.
Withdraw layshaft from the front
of the case
24.
Recover layshaft thrust plates
25.
Drop laygear into bottom of case
and withdraw input shaft and bearing
26.
Recover mainshaft needle roller
bearing and third/fourth synchro hub and rings
27.
Withdraw mainshaft & bearing
from rear of case (hold up by rear of mainshaft and tap case gently downwards
assistant required)
28.
Remove laygear and its needle
roller bearings from main case
29.
Inspect layshaft and needle roller
bearings if pitted or worn replace
30.
Inspect mainshaft nose and needle
roller bearing if pitted or worn the mainshaft will have to be disassembled
and the mainshaft re-tipped
31.
Measure the thrust washer
clearances if over spec the mainshaft will have to be disassembled and parts
replaced
32.
Inspect the synchro ring to hub
gap if less than 1/16 inch the mainshaft will have to be disassembled and
rings replaced
33.
Inspect the gear teeth
- if they are chipped, blackened, missing or worn the mainshaft will have
to be disassembled and parts replaced
34.
Inspect the synchro dog teeth
if badly rounded or worn the mainshaft will have to be disassembled and parts
replaced
35.
Slide the first / second hub back
and forth if the action is weak then the mainshaft and hubs will have to be
disassembled and springs replaced. Ditto the loose third / fourth hub but be
careful or springs and balls will fly!
36.
Inspect the main bearing for
roughness (this double row bearing rarely fails)
37.
Inspect the rear spacer if
this is loose the lock tab can be released and the nut tightened before re
securing the locktab
38.
Inspect laygear teeth if worn,
chipped, etc replace laygear
39.
Inspect input shaft for wear
40.
Inspect main case for wear and
cracks
41.
Release lockwasher behind front
nut
42.
Undo front nut
43.
Slide off the gears, etc. keeping
them in order
44.
The first gear and main bearing
are pressed on from the rear of the shaft and need not be disturbed unless they
need replacing
45.
Clean all parts thoroughly and
lightly oil
46.
Reassemble in reverse order,
replacing worn parts
47.
Fit new lockwasher and nut
48.
Stake lockwasher into nut recesses
49.
Knock back the lockwasher
50.
Undo retaining nut (left hand
thread!)
51.
Press off bearing
52.
Press on new bearing (circlip
towards the front)
53.
Do up nut
54.
Secure lockwasher
55.
Clean all parts thoroughly
lightly oil shafts / bearings
56.
Place the roller bearings inside
the laygear and place in the bottom of the case
57.
Insert the input shaft tap the
bearing into place
58.
Stand case on end and place
mainshaft needle roller bearing in the input shaft recess
59.
Place fourth / third synchro hub
and rings in place on the input shaft cone
60.
Insert mainshaft from rear (top)
and line up dowel in case with cut-out in bearing housing
61.
Tap main bearing housing into
case, guiding the mainshaft into the roller bearing at the same time
62.
Ensure that the main bearing and
input bearings are fully seated in their housings and that there is not
excessive end float on the fourth / third synchro hub
63.
Insert the laygear end thrust
washers and align the laygear (a thin rod helps here)
64.
Insert the layshaft from the front
and align the cut-out in the front end with the recess in the front plate
65.
Recheck the laygear end float
66.
Replace the front cover and
measure the gap between the cover and the case subtract 12 thou from this
figure and note the result
67.
Remove end cover and fit new
gasket
68.
Fit shims to the thickness of the
result of 66 above to plus 1 or minus 0 thou
69.
Fit front cover
70.
Fit the clutch fork and pivot bolt
71.
Replace the reverse gear in the
case and insert the shaft from the rear
72.
Align the locking hole (slot in
the end helps turn the shaft) and replace locking bolt & tab / lockwasher
73.
Place the selectors on the synchro
hubs and reverse gear
74.
Insert the selector rods from the
rear of the case and replace locking bolts
75.
Replace detent plungers, springs
and retaining bolts
76.
Fit side plate with new gasket
77.
Fit oil drain plug
78.
Fit the adapter housing
79.
Fit the selector interlock plate
80.
Remove filter cover and filter screen
81.
Undo relief valve plug and remove
relief valve
82.
Undo pump plug and remove pump
(don't lose the ball bearing)
83.
Undo the bolts holding the ID
plate and remove solenoid (don't lose the ball bearing)
84.
Undo nuts holding the case
together
85.
Separate the halves
86.
Undo the four nuts holding the
piston operating bars
87.
Withdraw the sliding member
refit bars and nuts to retain springs and spacers
88.
Using thin nosed pliers, pull out
the operating pistons
89.
Remove the speedo drive bearing
and pinion
90.
Clamp the drive flange and undo
the retaining nut
91.
Withdraw the flange and rear oil
seal
92.
Examine the teeth inside the
annulus for wear
93.
Examine the one way clutch for
correct operation
94.
Examine the planet gear teeth for
wear and the bearings for smooth operation
95.
Examine the sun gear teeth for
wear
96.
Examine the sliding member bearing
for smooth operation
97.
Examine the cone clutch for
burning, loose rivets and wear
98.
Examine the bronze bushing in the
front casing (or thrust washer) for wear or missing parts (if in need of repair,
send away to ORS)
99.
Examine the relief valve and pump
for wear or heavy scoring
100.
Examine ball valve seats for
correct seating
101.
Examine the front casing for loose
circlips
102.
Place the pump one way valve
spring in its recess in the pump retaining screw and ensure that it stands 1/16
to 1/8 inch proud of the surface if not then gently stretch the spring by
running a thin screwdriver up the coils sideways
103.
Ensure there are no sharp edges on
the pump retaining screw that will catch on the spring lightly chamfer using
a drill if necessary
104.
Clean all parts thoroughly
lightly oil bearings and gear assemblies
105.
Renew O rings on operating
pistons, lightly oil and fit to front case
106.
Refit sliding member (cut-outs on
bars face forward)
107.
Fit new rear oil seal, lightly oil
seal surface
108.
Fit drive flange and torque nut to
55 / 60 ft lbs
109.
Align the marks on the planet gear
and insert into annulus gear
110.
Apply a thin coating of Loctite
(red) to the mating surfaces and loosely assemble the front and rear cases
111.
Align the internal splines and
slide the unit temporarily onto the gearbox mainshaft to ensure correct
alignment
112.
Tighten nuts clamping the two
halves and remove unit from mainshaft take care not to rotate drive flange
from now on
113.
Renew O rings on the relief
valve assembly and fit to case
114.
Renew O rings on the pump
assembly and fit to case note that the flattened side of the pump operating
shaft faces rearwards against the case
115.
Fit the new filter screen and
filter cover
116.
Renew O rings on the
solenoid assembly and fit to the case
117.
Renew the O ring on the
speedo drive bearing
118.
Fit speedo pinion and bearing into
case
119.
Place new gasket on gearbox
adapter housing
120.
Fit the circlip, locating ball and
pump drive cam to the gearbox mainshaft
121.
Rotate the mainshaft so that the
cam lobe is uppermost
122.
Slide the OD unit onto the
mainshaft
123.
If it fails to reach the studs
the internal splines are not aligned remove OD and using two spanners to
lift the operating bars, use a long screwdriver to rotate the cone clutch until
the splines are aligned
124.
If it fails to mate within
3/8 inch then the pump operating roller is caught on the cam, use a thin long
screwdriver to depress the pump plunger
125.
Fit the retaining nuts, note
that some must be fitted with the OD unit slightly raised from the adapter
housing
126.
Fit a new gasket to the remote
tower housing and fit the housing, locating the plastic bush into its hole in
the selector arm
127.
Finally
- check the gearlever anti rattle spring & plunger in the tower for
presence and free operation