Subaru IMPREZA GD 2007 Series Manual page 3033

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MANUAL TRANSMISSION AND DIFFERENTIAL
31.General Diagnostic Table
A: INSPECTION
1. MANUAL TRANSMISSION
Symptom
1. Gears are difficult to intermesh.
NOTE:
If it is difficult to shift, there are two possi-
ble causes. One is a defective gear shift
system and the other is defective trans-
mission. However, if the operation is
heavy and engagement of the gears is dif-
ficult, a defective clutch disengagement
may also be responsible. Check whether
the clutch is correctly functioning, before
checking the gear shift system and trans-
mission.
2. The gear is slipping out
• Gear slips out when coasting on rough
road.
• The gear slips out when accelerating
3. Abnormal noise is emitted from the
transmission
NOTE:
If a noise is heard when the vehicle is
parked with its engine idling and if a noise
ceases when the clutch is disengaged, it
may be considered that the noise is com-
ing from the transmission.
General Diagnostic Table
Possible cause
(a) Worn, damaged or burred chamfer at
internal spline of the sleeve and reverse
driven gear
(b) Gear spline wear, damage, dents
(c) Worn or scratched bushings
(d) Incorrect contact or wear between
synchronizer ring and gear cone
(a) Defective pitching stopper adjustment
(b) Loose engine mounting bolts
(c) Worn fork shifter, broken shifter fork
rail spring
(d) Worn or damaged ball bearing
(e) Excessive clearance between splines
of synchronizer hub and synchronizer
sleeve
(f) Worn teeth steps on synchronizer hub
(caused by slippage of 3rd gear)
(g) Worn 1st driven gear, needle bearing
and race
(h) Worn 2nd driven gear, needle bearing
and race
(i) Worn 3rd drive gear and bushing
(j) Worn 4th drive gear and bushing
(k) Worn 5th drive gear and bushing
(l) Worn 6th drive gear and bushing
(m) Worn reverse idler gear and bushing
(a) Insufficient or improper lubrication
(b) Worn or damaged gears and bearings
NOTE:
If the trouble is only wear of the gear teeth
surfaces, only a high whirring noise will
occur at high speeds, but if any part is bro-
ken, rhythmical clicking sounds will be
heard even at low speeds.
6MT-128
Corrective action
Replace.
Replace.
Replace.
Repair or replace.
Adjust.
Tighten or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Lubricate with specified oil or replace.
Replace.