1. Check if you clearly understand what the client's problem is. If necessary, reproduce the problem condition on the vehicle.
2. If the problem cannot be reproduced, perform a road test and/or visual inspection using the following table.
3. If a visual check can clearly identify the problem, repair it and check if the system now functions correctly.
4. If the problem cannot be clearly identified, use the Symptom Table to identify the problem.
Visual Inspection Table
Mechanical factors:
- Leakage of working fluid in the hydraulic clutch
- Visibly damaged or worn parts
- Loose or missing bolts or nuts
Symptom Table - Clutch Operation
|
State |
Possible Causes |
Action |
|
• Clutch does not disengage |
• Air in the hydraulic clutch |
• Bleed the hydraulic clutch system. For more information, refer to Clutch Control - Bleeding available in this section.. |
|
•Too low brake fluid level |
• Top up the 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 |
•Go to System Check F. |
Manual transmission iB5/ Manual transmission MTX-75
Diagnosis of a manual transmission is divided into three parts (Main problems A, B and C). Before repairing or replacing the iB5 manual transmission, the following checks must be carried out:
Main problem A: Poor shifting
1. If you can easily select 1st or 2nd gear with the engine running and the parking brake applied, the clutch is good. If you cannot select a gear, check the clutch. See Section 308-00 for more information.
2. Check gear selector: Refer to Section 308-06A / 308-06B / 308-06C for more information. or
3. Check the transmission fluid level and correct if necessary. For more information, please refer to the Specification available in this section.
Main problem B: Noises in the gearbox
- If noises are registered in the transmission, first check the transmission fluid level. If the gearbox is damaged due to lack of 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/transmission guide bushings are installed.
Main problem C: Oil leakage
- Check to see if it is the transmission fluid that is actually leaking, not the brake fluid (from hydraulic clutch) or motor oil.
- Check the transmission fluid level and drain any excess fluid if necessary. For more information, please refer to the General Specifications available in this section.
- Use a fluorescent test fluid and a UV leak tester to determine the source of the oil leak.
- Thoroughly clean the gearbox and surrounding areas before road testing.
Main problem A: Poor shifting
|
State |
Possible Causes |
Action |
|
• Significant effort required when shifting gears |
• Clutch not fully engaged |
•Check the clutch. For more information, refer to System Check - Coupling available in this section.. |
|
•Installation position of clutch disc |
• Remove the gearbox. See Section 308-03A / 308-03B / 308-03C for more information. or Check the installation position of the clutch disc. |
|
|
• Damage to the internal shift mechanism or synchronizer |
• Remove gearbox and inspect internal shifter and synchronizers, replace if necessary. Refer to Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Wrong transmission fluid |
•Check if the transmission contains the prescribed transmission fluid. Fill it up if necessary. For more information, please refer to the Specification available in this section.. |
|
|
• Transmission slips out of gear when moving. |
• Hardened shift lever boot |
•Check the outer boot on the gear lever and replace if necessary. See Section 308-06A / 308-06B / 308-06C for more information. or |
|
• Looseness, malfunction, or twisting of engine/gearbox mounts |
•Check engine/gearbox mounts and replace if necessary. |
|
|
• Noise when shifting from one gear to another |
• Clutch not fully engaged. |
•Check the clutch. For more information, refer to System Check - Coupling available in this section.. |
|
• Worn or damaged shift forks, synchronizer rings or synchronizer clutches (usually occurs after a long run) |
•Check the elements for damage and replace if necessary. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Inability to engage gears |
•Faulty shift cables |
•Check shift cables for damage. Replace elements if necessary. See Section 308-06A / 308-06B / 308-06C for more information. or |
|
• Jamming in the internal mechanism |
• Disconnect the shift cables from the gearbox and check if the internal shift mechanism is limited in its movement, if so, remove and disassemble the gearbox. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Shift blocked in first gear |
•Faulty shift cables |
•Check shift cables for damage. Replace elements if necessary. See Section 308-06A / 308-06B / 308-06C for more information. or |
|
• Malfunction of the internal gearshift mechanism |
• Disconnect the shift cables from the gearbox and check if the shift is still blocked; if so, remove and disassemble the gearbox. See Section 308-03A / 308-03B / 308-03C for more information. or |
Main problem B: Noises in the gearbox
|
State |
Possible Causes |
Action |
|
• Slight humming, rattling or metallic grinding coming from the transmission in neutral |
• Rotational vibration coming from the engine is not sufficiently damped by the clutch. |
•These noises do not affect the operation and life of the gearbox. |
|
• Momentary creaking when shifting gears |
• Insufficient gear synchronization |
•Install a complete set of synchronizer (synchronizer hub and synchronizer rings) and replace the two gears included in the synchronizer block. Due to the presence of various changes and the difficulty in assessing the level of wear, a complete replacement is recommended (as described above). See Section 308-03A / 308-03B / 308-03C for more information. or |
|
• Clutch failure |
•Check the clutch. For more information, refer to System Check - Coupling available in this section.. |
Main problem C: Oil leakage
|
State |
Possible Causes |
Action |
|
• Oil leakage |
• Damage to the sealing lip of the input shaft oil seal |
• Replace the input shaft oil seal. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
• Oil leakage between sections of the gearbox housing or from the mating flange of the gear selector mechanism. |
• Disassemble the gearbox, clean the mating surfaces (check surfaces for defects). Install a new oil seal to the gearbox. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Transmission fluid level too high or transmission fluid not up to specification |
•Check the transmission fluid level. Drain if necessary and refill with new transmission fluid. For more information, please refer to the Specification available in this section.. |
|
|
•Check that the leak is not coming from any other unit (engine or power steering). |
•Clearly identify the source of the leak. |
|
|
• Worn or damaged items |
•Before removing the gearbox, remove the dust cover from the clutch housing. Check the clutch slave cylinder, transmission input shaft oil seal, front axle oil seals, and gear lever shaft oil seal for leaks. |
|
|
• Weak transmission fluid mist from transmission breather |
• A slight mist of transmission fluid from the transmission breather is normal. If transmission fluid drops are found in the transmission breather, clean the breather. |
Common problems:
|
State |
Possible Causes |
Action |
|
• Noises in forward gears |
•Too low transmission fluid level |
•Add transmission fluid. For more information, please refer to the Specification available in this section.. |
|
•Engine/gearbox touching chassis/body |
• Check for touch points or check for bad engine/gearbox mounts and replace if necessary. |
|
|
• Loose engine/gearbox flange bolts |
• Tighten the engine/transmission flange bolts. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Transmission failure, wear or damage to components. |
• Remove the gearbox and disassemble it. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
•Inability to select reverse gear |
• Faulty reversing light switch or improper reversing light switch setting. |
•Check the reverse light switch and replace if necessary. |
|
• Wear or damage to internal components |
•Remove the gearbox, disassemble it and check the relevant parts for damage. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
• Internal gearshift mechanism is blocked by a foreign object. |
• Remove the gearbox and disassemble it. See Section 308-03A / 308-03B / 308-03C for more information. or |
|
|
•Inoperability of the gear lever - inability to select gears |
•Faulty shift cables |
• CHECK shift cables and ADJUST if necessary. See Section 308-06A / 308-06B / 308-06C for more information. or |
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