1. Check if you have a clear understanding of the customer's problem. If necessary, reproduce the problematic condition on the car.
2. If the problem cannot be reproduced, perform a road test and/or visual inspection using the following table.
3. If the fault can be clearly identified by visual inspection, correct it and check whether the system now functions properly.
4. If the fault cannot be clearly identified, use the Fault Symptom Table to identify it.
Visual inspection table
Mechanical factors:
- Leakage of working fluid in the clutch hydraulic drive
- Visibly damaged or worn components
- Loose or missing bolts or nuts
Fault Symptoms Table - Clutch Operation
|
State |
Possible Causes |
Action |
|
•The clutch does not disengage |
•Air in the clutch hydraulic drive |
•Bleed the clutch hydraulic system. For more information, refer to Clutch Hydraulic System - Bleeding in this section.. |
|
•Brake fluid level too low |
•Add brake fluid. |
|
|
•Clutch pedal travel out of specification |
•Replace the clutch pedal. |
|
|
•Leaks in the clutch hydraulic system |
•Leaks in the clutch master cylinder •Leaks in the clutch slave cylinder •Leaks in the hydraulic clutch system |
•Proceed to System F check. |
Manual transmission iB5/ Manual transmission MTX-75
Manual transmission diagnostics are divided into three parts (Main problems A, B and C). Before repairing or replacing the iB5 manual transmission, the following checks must be performed:
Main Problem A: Poor Gear Shifting
1. If you can select 1st or 2nd gear without difficulty with the engine running and the parking brake applied, the clutch is OK. If you cannot select a gear, check the clutch. Refer to Section 308-00 for additional information.
2. Check the gear selector mechanism: For additional information, refer to Section 308-06A / 308-06B / 308-06C. or
3. Check the transmission fluid level and correct it if necessary. For more information, refer to the Specifications available in this section.
Main problem B: Noises in the gearbox
- If noise is detected in the gearbox, first check the transmission fluid level. If the gearbox is damaged due to insufficient fluid, replace it (iB5 gearbox). Determine how much fluid is left and make a note of this on the paid warranty form.
- Make sure the engine/gearbox guide bushings are installed.
Main Problem C: Oil Leak
- Check to see if it is transmission fluid that is leaking, and not brake fluid (from the clutch hydraulic system) or engine oil.
- Check the transmission fluid level and drain any excess fluid as necessary. For more information, refer to the General Specifications found in this section.
- Use fluorescent test fluid and an ultraviolet leak tester to determine the source of the oil leak.
- Before road testing, thoroughly clean the transmission and surrounding areas.
Main Problem A: Poor Gear Shifting
|
State |
Possible Causes |
Action |
|
•Significant effort required when changing gears |
•Clutch not fully engaged |
•Check the clutch. For more information, refer to Checking the System - Clutch in this section.. |
|
• Clutch slave disc installation position |
•Remove the transmission. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or Check the installation position of the clutch disc. |
|
|
•Damage to the internal shift mechanism or synchronizer |
•Remove the transmission and inspect the internal shift mechanism and synchronizers, replace if necessary. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Incorrect transmission fluid |
•Check that the transmission fluid is correct. Top up if necessary. For more information, refer to the Specifications in this section. |
|
|
•The transmission jumps out of engagement while moving. |
•Hardened gear shift boot |
•Check the outer boot on the shift lever and replace it if necessary. For additional information, refer to Section 308-06A / 308-06B / 308-06C. or |
|
•Loose, faulty or twisted engine/gearbox mounts |
•Check engine/gearbox mounts and replace if necessary. |
|
|
•Noise when shifting from one gear to another |
•The clutch is not fully engaged. |
•Check the clutch. For more information, refer to Checking the System - Clutch in this section.. |
|
•Worn or damaged gear shift forks, synchronizer rings or synchronizer sleeves (usually occurs after high mileage) |
•Check components for damage and replace if necessary. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Inability to engage gears |
•Faulty gear shift cables |
•Check shift cables for damage. Replace components if necessary. For additional information, refer to Section 308-06A / 308-06B / 308-06C. or |
|
• Seizure in the internal mechanism |
•Disconnect the shift cables from the transmission and check to see if the internal shift mechanism is restricted in its movement, if so, remove and disassemble the transmission. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Shifting is locked in first gear |
•Faulty gear shift cables |
•Check shift cables for damage. Replace components if necessary. For additional information, refer to Section 308-06A / 308-06B / 308-06C. or |
|
• Malfunction of the internal gear shift mechanism |
•Disconnect the gear shift cables from the transmission and check if the gear shift is still locked; if so, remove and disassemble the transmission. For additional information, refer to Section 308-03A/308-03B/308-03C. or |
Main problem B: Noises in the gearbox
|
State |
Possible Causes |
Action |
|
•A slight humming, rattling or metallic grinding noise coming from the transmission when in neutral |
•The rotational vibration coming from the engine is not sufficiently damped by the clutch. |
•These noises do not affect the operation and service life of the gearbox. |
|
•Short-term creaking when shifting gears |
•Insufficient gear synchronization |
•Install the complete synchronizer assembly (synchronizer hub and synchronizer rings) and replace the two gears comprising the synchronizer unit. Due to the various variations and the difficulty in assessing the level of wear, a complete replacement (as described above) is recommended. For further information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
•Clutch failure |
•Check the clutch. For more information, refer to Checking the System - Clutch in this section.. |
Main Problem C: Oil Leak
|
State |
Possible Causes |
Action |
|
•Oil leak |
• Damage to the sealing lip of the primary shaft oil seal |
•Replace the input shaft oil seal. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
• Oil leak between sections of the gearbox housing or from the mating flange of the gear selection mechanism. |
• Disassemble the transmission, clean the mating surfaces (check the surfaces for defects). Install a new oil seal on the transmission. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Transmission fluid level too high or transmission fluid not meeting specification |
•Check the transmission fluid level. Drain and replace with new transmission fluid if necessary. For more information, refer to the Specifications available in this section.. |
|
|
•Make sure the leak does not come from any other component (engine or power steering). |
•Clearly identify the source of the leak. |
|
|
•Worn or damaged parts |
•Before removing the gearbox, remove the dust cover from the clutch housing. Check the clutch slave cylinder, gearbox input shaft oil seal, front axle shaft oil seals and gearshift lever shaft oil seal for leaks. |
|
|
•Weak mist of transmission fluid from the gearbox breather |
•It is normal for transmission fluid to mist out of the transmission breather. If you see drops of transmission fluid in the transmission breather, clean the breather. |
Common problems:
|
State |
Possible Causes |
Action |
|
•Noises in forward gears |
•Transmission fluid level too low |
•Add transmission fluid. For more information, refer to the Specifications available in this section.. |
|
•Engine/gearbox touching chassis/body |
•Check for contact points or check for faulty engine/transmission mounts and replace if necessary. |
|
|
•Loosening of engine/gearbox flange bolts |
•Tighten the engine/transmission flange bolts. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Gearbox malfunction, wear or damage to components. |
•Remove the transmission and disassemble it. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Inability to select reverse gear |
•Faulty reversing light switch or incorrect installation of the reversing light switch. |
•Check the reversing light switch and replace it if necessary. |
|
•Wear or damage to internal components |
•Remove the transmission, disassemble it and inspect the related components for damage. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•The internal gear shift mechanism is blocked by a foreign object. |
•Remove the transmission and disassemble it. For additional information, refer to Section 308-03A / 308-03B / 308-03C. or |
|
|
•Gear shift lever inoperative - unable to select gears |
•Faulty gear shift cables |
•CHECK the shift cables and ADJUST them if necessary. For additional information, refer to Section 308-06A / 308-06B / 308-06C. or |
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