MG MGA Twin Cam Workshop Manual page 98

F
THE GEARBOX
Replace the interlock ann on the rear c:xt. e osioo side
cover OaQge and rdit the cover. Replace the propeller
shaft driving ftange, out, and spring washer.
Section
F.8
ASSEMBLING mE GEARBOX
Place the layshaft gear in the box complete with end
thrust washers but do not fit the shaft.
Assemble and replace the first motion shaft, and
replace the 18 needle-roller bearings.
Insert the third motion shaft from the rear; use the
gasket fitted between the box and rear extension to
position the dowel and
bearing
housing. Push home the
shaft, the rear bearing and housing. and enter the spigot
in the needle-roUer race of the first motion shaft.
Fit the layshaft and thrust washers. Line up the cut-
away
portion of the front end
witb the lay•hnfi locoting
groove in the front cover.
Fit tbe reverse gear and shaft; tighten and lock the
set screw.
Refit the front end cover (see Section F.IO), replacing
the bearing shims that were removed on dismantling.
Refit the clutch lever and fork.
Fit the selectors to the shifter shaft rear ends.
Bolt the shifter shaft locating block to the rear face of
the gearbox; replace the balls and
springs
and
insert~
shifter shafts.
Position the gear change forks in the box in the
foUowing sequence: re\-erse, first and second, third and
top. Push the shifter shafts into the box and through
the forks; insen, tighten, and wire up the set
screws.
Position the <elednr<: nn the rear end< of the <hiller
shafts; insert, tighten, and wire up the set screws.
Relit the gearbox rear extension.
Locate the change speed gate in the gearbox and fit
the side cover, using a new joint as necessary.
Screw in the speedometer drive gear assembly, plugs,
and brcnther.
The remote control assembly is filled to the gearbox,
and the gearbox filled with oil, after the power unit is
instaUed in the chassis.
Section F.9
RENEWING THE GEARBOX EXTENSI ON
on.
SEAL
Remove the four bolts securing the propeller shaft
front universal joint to the gearbox flange.
F.6
Hold the flange steady with Service tool 18G34A and
remove the nut and spring washer.
Remove the flanJC.
Using Service tool 180389 with adaptor 18G389B,
withdraw the old seal.
Use Service tool 18GI34 with adaptor 18Gl34N to lit
the new seal.
Relit the flange, out, and spring washer.
Section F. IO
REF II I'h " G THE GEARBOX FRONT COVEll
To prevent oil lealcing past the gearbox front cover
oil seal the cover must be correctly fined to ensure
that the
seal
is concentric with the first motion shaft.
When
refitting the
cover
proceed as
foUows.
aean off the cover and examine
it carefully for
burrs and bruising, particularly around the bore, stud
holes, and machined surfaces. Check the flat surfaces
for twist and warp, and oorrect it if necessary.
If
the
condition is too bad to correct, fit a n. e w cover.
Remove and discard the front cover to gearbox
gasket and clean off the flat surfaces around the base of
aU studs.
Offer the front cover (less oil seal) to the gearbc.x
and push it fully home on the studs. The cover should
be free
to move in aU
directions, and points at which
the holes may be binding on the nuds must be relieved
until the OO\"Cr is free to
ftoat.
Remove the covecr and, usios Service
tool
180134
with adaptor 18G134N, lit the oil seal so that its lip
faces inwards towa. r ds the gearbox. Ughtly grease and
fit a new gasket to the gearbox front face, then fit the
centralizer (Service tool 180598) to the bore of the front
cover a nd push it in until it is tight. Ugbtly oil the seal
and pass the cover over the nrst motion shaft, taking
particular care not to cut or damage the knife edge of the
seal.
Keep the centralizer firmly in position, push the cover
onto the studs, and lit the spring washers and nuts,
tightening the nuts finger-tight only. Use a suitable
socket spanner and long extensioo to tighten the nuts a
half-tum at a time by diametrical selection until all nuts
are fully tightened.
Remove the centrallzer an<l reftt the Clutch operating
components.
MGA
(!'win Cam).
Issue 4. 31403