Page 61
Manual 5-speed transmissions
For work on the transmission, it will not
usually be necessary to separate the engine
and transmission. However, the flywheel
and starter motor must always be dis-
mantled first.
Dismantling
(Proceed in the following order as far as
/ necessary in order to remove whichever
component needs attentions)
1.Clean the transmission case and drain
the oil:
a. with the transmission horizontal and
b. with the transmission vertical. Let
the oil drain out of the primary drive
case.
2.Remove the following covers:
- Front cover on the primary drive
ease.
~ Side cover on the primary drive case
(there will still be same oil in the
primary gear case).
Side cover on transmission case.
- Final drive cover.
3,Measure the backlash between the pi-
nion and crown wheel, see section 473.
4,.Remove the differential bearing seat
retaining bolts and remove the seats
and inner driver using tool 83 90 270
and puller 87 90 776,
| Save the spring and plunger at the shaft
end of the driver, and the shims, which
can be re-used on the condition that the
1 differential gear backlash has not been
: altered by the exchange of some com-
hist ponents.
5.Remove the differential assembly. For
dismantling of the differential assembly
see section 473.
6.Measure the clearance between the
Pinion and the centre of the crown
wheel. See section 473.
f 471-22
——_ hats
Important
Before dismantling the transmission,
always measure the posilions of Lhe
pinion gear and crown wheel. This is to
check whether there is any error in
their locations. If the pinion and crown
wheel assembly is relatively new, i.e.
if it has done less than 6,000 miles
(10,000 km), it can be adjusted, but if
the mileage is any greater the gears
will have worn themselves into a given
position. In the latter case, they
should be reassembled jn the same
measured positions which they occu-
pied before being dismantled.
+
Page 62
7.Remove the dowel in the qgear-shift
fork for 5th gear.
§.Move the gearwheel for reverse into
reverse-qear position and select 5th
qear.
9a. Free the shaft (ower sprocket) tab
washer from the input shaft.
h. Remove the nul.
10. Remove the chain tensioner.
ll.Remove the circlip from in front of the
upper sprocket bearing.
12.Remove the sprockets and the chains
simultaneously. Slide harmnmer 83 90 270
and puller 83 90 891 may be needed to
remove the sprockets.
i itd
AL lite
Page 63
13. Separate the constant mesh gear from
the layshaft gear cluster by removing
the circlip from the groove and sliding
the synchromesh sleeve towards the
gear.
471-24
Page 64
14,.Remove the locking plate for the lay-
shaft. and reverse gear shaft. Using
tools 85 90 049 and 83 90 270, withdraw
the layshaft gear cluster and then re-
move the corstant mesh gear, together
with the syneromesh sleeve and thrust
washer, through the side of the trans-
mission case.
15.Remove the bolls and the oil catcher
from the input shaft bearing case. Then
remove the bearing case using Slide
hammer 8390270 and adapter
87 90 917,
P4e
471-25
Page 65
16.Slide the gear selector for fifth gear to
the full extent of its travel and then
remove the selector fork and the syn-
chromesh sleeve.
| 17.Remove the gearwheel and shaft for
reverse gear. Fit locking tool 87 90 503
to the reverse gearwheel. Release the
circlip and unscrew the nut securing the
synchro hub for fifth gear. Retain the
hub and spacer.
471-26
1, Gear selector to stop
?. Hole for locking stud
Page 66
18. Remove all primary gear case retaining
bolts and drift in the dowels sa that the
primary gear case can be separated
from the gearbox housing. (The 5th
speed selector will remain in the
housing and can be removed later. File
away any burrs there may be round the
hole in the shaft, so that the aperture
in the gear housing will not be damaged
on reassembly).
19,Remove the layshaft and the layshaft
gear cluster. Retain the needle bearings
and thrust washer for re-use.
471-27
Page 67
20.Remove the selector shafts and the
selectors (first, seond, third and fourth
speeds on the inner shaft). Remove the
selectors for first and second gears
together with their synchromesh units.
Remove the selector for reverse to-
gether with the shaft for fifth gear and
reverse gear.
21. The selector shafts should be removed
from the front. The aperture for the
taper pin should be filed so that it is
free of burrs so that the aperture is not
damaged. Remove the selector, double
lockout and spring later. Retain the
selector ball and quide pin
22.Remove the four bolts retaining the
pinion shaft bearing housing. Install tool
8790909 and press out the pinion
shaft. Keep the gearwheels, sleeves,
washers and shims.
471—28
Page 68
Assembly
Having removed the component that needs
attention, clean all fragments of old gas-
kets and all traces of old sealing compound
off the covers and flanges. Inspect the
transmission case and all dismantled parts
and wash them in kerosene or similar.
Lubericate all components as detailed in
the specifications section on lubricants.
Reassemble the transmission, following the
procedure described below:
1.Adjust the differential bearings to the
correct compression. See section 473.
2.Screw the two locating studs (tool
87 90 438) into the transmission case.
Then shim and locate the pinion shaft
assembly. Tap the assembly gently into
position, using a plastic mallet, drift
83 90 114, and sleeve 83 90 148. Refit
the retaining bolts for the bearing
housing, tightening them to a torque of
20-25 Nm (2 = 2.5 kgfm; 15-18.5 |b ft).
Finally, apply Loctite to the bolts.
3.a. Before fitting the reverse gear on
the pinion shaft, check the distance
between the mating surface for the
primary gear housing and the pinion
shaft nut. The distance must be
7.677 in-7.681 in (195.0-195.1 mm).
If it is not, shims must be placed
between the nut and the reverse
gear. Shims are available in thick-
nesses of 0.0118 in (0.30 mm), 0.0157
in (0.40 mm) and 0.0197 in (0.050
mm). If the position of the pinion
shaft is unchanged, the shims used
earlier can be replaced.
bh. When using measuring tao]
A790 552, the procedure af shim
ming is Lhe following:
Fit the measuring tool in the gear-
box housing as illustrated, and mea-
sure the distance between tool and
nut with the aid of a feeler gauge.
rit shims with a thickness equiva-
lent to that of the feeler gauge.
471-29
Page 69
4.Fit lhe reverse gear using sleeve
83 90 148.
2.Fit the Ist-speed gear on the bearing
sleeve of the reverse qear.
6.Fit Ist-2nd speed synchromesh hub, rit
Ist-2nd speed gear shift fork into Ist-
2nd speed synchromesh sleeve and fit
these on the synchromesh hub. Fit Ist
2nd speed gear shift fork into Ist-2nd
speed synchromesh sleeve and fit these
on the synchramesh hub.
| 7.Fit the 2nd speed gear sleeve with tool
83 90 148 and fil the 2nd speed gear an
the sleeve.
8.Fit the spacer, the sleeve for 3rd gear
with tool 8390148 and fit the 3rd
speed gear on the sleeve.
9.Fit 3rd-4th gear synchromesh hub. Fil
/ 3rd-4th speed gear shift fork into 3rd-
4th gear synchramesl sleeve and fit
\ these an the synchramesh hub.
Fit the bush for the 4th speed year and
fit the gear onta the bush. Fit the ball
f bearing bush.
10.1f the selector shaft has been removed,
he refit it Logether with the double lock.
out guide pin
4 471-30
Synchro sleeves
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1l.Ease the synchromesh sleeves onto the
Pinion shaft in the neutral position and
fit the gear shift shaft for Ilst-2nd
speed and J3rd-4th speed gear-shift
forks.
12,Refit the reverse selector shaft with
selector. Seal the shafl stop bolt with
Loctite 242 and tighten.
13.Fit the 5th speed selector on the re-
verse selector shaft.
14.Fit the needle bearing to the layshaft
gear cluster and place the latter inside
the gearbox housing.
15. Fit the layshaft and raise the layshaft
gear cluster to line it up with the shaft.
Insert the shaft far enough to hold the
gears in position. Fit the thrust washer
later.
16.Fit the spacer the 5th speed synchro
hub and the circlip on the pinion shaft.
Fit the requisite shims between the hub
and sleeve so that there is na play
between the parts on the pinion. shaft.
The shim thieknesses available are 0.30
mm and 0.40 mm. The circlip, the hub
and the spacer should then be removed.
17. Apply Loctite 510 sealing Compound to
the flange of the primary drive Casing
and bolt the casing to the gearbox
housing. Knock in the lacating studs
before fitting the bolts. Fit the spacer
to the pinion shaft. Fit the 5th speed
synchro hub,
Ave 4 34