DS 19 OPERATION No. DS 330-3 : Overhauling a gearbox. Op. DS 330-3 207
TOOLS
34 To assemble the mainshaft (see Pl. 52):
a) Fit on the mainshaft prepared in paragraph 28, the 3rd and 4th speed synchromesh (90) (the shouldered face
against the 3rd speed), the 4th speed loose pinion (36) with its needle bearing cage.
b) Place the assembly in the box by inclining the shaft towards the rear; engage it first into the bore of the rear
bearing.
c) Fit a paper joint on the front face of the casing, stick on with grease. Put the bearings (21) and (35) in position.
d) Put on the shaft (22), the 1st speed pinion (19) and the rear bearing (17) (mandrel MR-3045, see Pl. 65, fig. 1). Mandrel MR-3045
e) Put two gears in mesh and tighten the starting handle dog (11) to 72 to 87 ft/lbs (10 to 12 m.kg) (insert a
lockwasher) (spanner 1734-T, see Pl. 65, fig. 3). Turn over the lockwasher . . . . . . . . . . . . . . . . . . . . . . . . . . . Spanner 1734-T
f) Tighten the bevel pinion shaft nut (12) to 144 ft/lbs (20 m. kg). (Do not fit a lockwasher). If the nut (12) was
retained by a lockwasher, do not refit the nut on the lockwasher. Obtain from our Spare Parts Department, a
new nut with a thin collar No. DS 344-5.
35 Fit the mainshaft bearing cover plate (7) together with a paper joint smeared with grease and the adjusting shims
(9) determined in paragraph 28 “e” or “f”. Put the rear bearing in position. Fit the distance piece (18) and
the circlip (16) (circlip pliers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . circlip pliers
36 To adjust the bevel pinion shaft (see Pl. 52 and 59, fig. 1)
NOTE - This adjustment is of the greatest importance. Giving the teeth the correct bearing will ensure silence
and long service from the crown wheel and pinion. The setting dimension is given in millimetres and
hundredths of millimetres and is etched on the ground end of the bevel pinion.
This dimension represents the distance “y” which should exist when the adjustment is completed, between the
centre line of the differential shaft and the ground end of the bevel pinion.
This will vary with each crown wheel and pinion.
The adjustment of the bevel pinion setting should be made by using the adjusting fixture 2044-T, together with
the dial gauge 2437-T, see Pl. 59, fig. 1).
This fixture is constructed so that the distance between the centres of the semi-circular ground bearing faces
and the two ground bearing pads is 55 mm. This number is etched between the two pads.
The measurement should not be taken from the face of the joint of casing, as this differs in relation to the
centres of the differential bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dial gauge 2437-T
Adjusting fixture 2044-T
a) Fit the lower bearing cover plate (8) together with the adjusting shims (10) (determined in paragraph 29 “c”)
and a paper joint without Hermetic.
Tighten the screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 mm box spanner
b) Carefully clean the bearing faces for the differential bearings and the semi-circular faces of the adjusting
fixture 2044-T. All faces should be free from scratches or burrs.
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