DS 19 OPERATION No. DS 330-3 Overhauling a gearbox. Op. DS 330-3 209
TOOLS
Fit the cover, the 3rd and 4th speed selector fork together with its thrust pads (smear with grease to prevent
them falling out of position)
Make sure that the forks are properly engaged in the grooves of the sliding pinions. Fix the cover by the two
centring screws.
b) To adjust the 3rd speed cylinder.
Bring the base of the 4th speed synchro (90) as far as possible into contact with the thrust washer of the pinion,
by pushing on the selector shaft (61).
Measure the distance by which the shaft stands proud at “e” (see Pl. 55, fig. 5), use the straight edge MR-3377
(see Pl. 56, fig. 2), together with the dial gauge 2437-T. Set the dial gauge, by putting the fixture on a surface
plate. Set the dial at “0”. Mark the position of the needles. Put the straight edge on the thrust face of the
cylinders, on the cover, the pointer of the dial gauge in contact with the end of the shaft. Using a drift, maintain
a pressure of approximately 25 kg on the end of the shaft. Bring the needles of the dial to their original position
(setting position). Release the spindle of the dial gauge slowly, counting the number of turns and fractions of
turns. For example: a distance of 1.40 mm.
Measure the distance that the piston stands proud of the bearing face of the cylinder on the casing (see Fl. 55,
fig. 7).
Push the piston to the base of the cylinder.
Place a bush 20 mm high on the cylinder and measure the distance “d” between the face “x” of the bush and
the end of the piston by means of a depth gauge. For example: “d” = 18.65 mm.
The distance between the face of the piston and the bearing face of the cylinder on the cover is therefore
“e” = 20 - 18.65 = 1.35 mm.
In order to obtain a clearance of 0.1 to 0.3 mm between the face of the synchro and the thrust washer, the
adjusting washer should have a thickness of between
1.35 - 0.1 = 1.25 and 1.35- 0.3 = 1.05 mm.
Select from the adjusting washers sold by our Spare Parts Department, a washer of the appropriate thickness.
In the example a suitable washer would be 1.1 mm thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Depth gauge
c) To adjust the 1st speed cylinder.
Put the gearbox in the neutral position. Engage the 2nd speed as far as possible by pushing on the shaft (77).
Proceed as mentioned in paragraph ‘b’, the clearance obtained between the synchro and the reverse pinion
should be between 0.30 and 0.65 mm.
d) Fit on each cylinder the washers determined above.
e) Put the gearbox in the neutral position. Engage 3rd speed as far as possible by pushing on the shaft (61).
Carry out the same procedure for the 4th speed. Put the washers thus determined on the 4th speed cylinder.
Check that the other gears work normally by pushing successively on the shafts.
39 Remove the cover plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 mm box spanner
40 Fit the spring cups (compressor 1798-T, see Pl. 56, fig. 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compressor 1798-T
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