SAAB WIS ONLINE

INSPECTION

INSPECTION

MANUAL TRANSMISSION

Symptom Possible cause Remedy
1. Gears are difficult to intermesh.

Note

The cause for difficulty in shifting gears can be classified into two kinds: one is malfunction of the gear shift system and the other is malfunction of the transmission. However, if the operation is heavy and engagement of the gears is difficult, defective clutch disengagement may also be responsible. Check whether the clutch is correctly functioning, before checking the gear shift system and transmission.


(a) Worn, damaged or burred chamfer of internal spline of sleeve and reverse driven gear

Replace.

(b) Worn, damaged or burred chamfer of spline of gears

Replace.

(c) Worn or scratched bushings

Replace.

(d) Incorrect contact between synchronizer ring and gear cone or wear

Correct or replace.

2. Gear slips out.


• Gear slips out when coasting on rough road.

• Gear slips out during acceleration.


(a) Defective pitching stopper adjustment

Adjust.

(b) Loose engine mounting bolts

Tighten or replace.

(c) Worn fork shifter, broken shifter fork rail spring

Replace.

(d) Worn or damaged ball bearing

Replace.

(e) Excessive clearance between splines of synchronizer hub and synchronizer sleeve

Replace.

(f) Worn tooth step of synchronizer hub (responsible for slip-out of 3rd gear)

Replace.

(g) Worn 1st driven gear and driven shaft

Replace.

(h) Worn 2nd driven gear and bushing

Replace.

(i) Worn 3rd drive gear and needle bearing

Replace.

(j) Worn 4th drive gear and needle bearing

Replace.

(k) Worn reverse idler gear and bushing

Replace.

3. Unusual noise comes from transmission.

Note

If an unusual noise is heard when the vehicle is parked with its engine idling and if the noise ceases when the clutch is disengaged, it may be considered that the noise comes from the transmission.


(a) Insufficient or improper lubrication

Lubricate or replace with specified oil.

(b) Worn or damaged gears and bearings

Note

If the trouble is only wear of the tooth surfaces, merely a high roaring noise will occur at high speeds, but if any part is broken, rhythmical knocking sound will be heard even at low speeds.


Replace.



DIFFERENTIAL

Symptom Possible cause Remedy
1. Broken differential (case, gear, bearing, etc.)

Note

Noise will develop and finally it will become impossible to continue to run due to broken pieces obstructing the gear revolution.


(a) Insufficient or improper oil

Disassemble the differential and replace broken components and at the same time check other components for any trouble, and replace if necessary.

(b) Use of vehicle under severe conditions such as excessive load and improper use of clutch

Readjust the bearing preload and backlash and face contact of gears.

(c) Improper adjustment of taper roller bearing

Adjust.

(d) Improper adjustment of drive pinion and hypoid driven gear

Adjust.

(e) Excessive backlash due to worn differential side gear, washer or differential pinion vehicle under severe operating conditions.

Add recommended oil to specified level. Do not use the vehicle under severe operating conditions.

(f) Loose hypoid driven gear clamping bolts

Tighten.

2. Differential and hypoid gear noises

Troubles of the differential and hypoid gear always appear as noise problems. Therefore noise is the first indication of the trouble. However noises from the engine, muffler, tire, exhaust gas, bearing, body, etc. are easily mistaken for the differential noise. Pay special attention to the hypoid gear noise because it is easily confused with other gear noises. There are the following four kinds of noises.


• Gear noise when driving: If noise increases as vehicle speed increases it may be due to insufficient gear oil, incorrect gear engagement, damaged gears, etc.

• Gear noise when coasting: Damaged gears due to maladjusted bearings and incorrect shim adjustment

• Bearing noise when driving or when coasting: Cracked, broken or damaged bearings

• Noise which mainly occurs when turning: Unusual noise from differential side gear, differential pinion, differential pinion shaft, etc.


(a) Insufficient oil

Lubricate.

(b) Improper adjustment of hypoid driven gear and drive pinion

Check tooth contact.

(c) Worn teeth of hypoid driven gear and drive pinion

Replace as a set.

Readjust the bearing preload.

(d) Loose roller bearing

Readjust the hypoid driven gear to drive pinion backlash and check tooth contact.

(e) Distorted hypoid driven gear or differential case

Replace.

(f) Worn washer and differential pinion shaft

Replace.