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Kia & Hyundai 6 Speed Manual Gearbox Issue | 3rd-4th-5th-6th Gear Crunch | Eco Torque

Updated: May 4, 2023

We are seeing an increasing amount of Kia & Hyundai 6 speed models with a common gear crunching issue. This can happen in 3rd, 4th, 5th and 6th gear, or a combination of them. More details in the article as well as repair solutions.


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We have seen a common issue arising with a particular gearbox fitted to Hyundai & Kia models effecting gear selection. The issue results in an audible grinding noise when trying to select gears. After investigating we found the following issue.


Symptoms & Repairs

The fault most commonly occurs when the driver tries to select a gear and a loud audible grinding/graunching sound is heard. This can be in 3rd, 4th, 5th and 6th gear, or a combination of those listed.

It is possible that a clutch issue may also be present and the cause, however it is not common to have issues in just the high gears, it is normally the opposite way round, with reverse, 1st and 2nd being difficult to select.

After stripping the units we discovered and interesting fault with the synchromesh rings.

Kia Hyundai gearbox synchromesh, eco torque gearbox repair
Broken synchromesh causing grinding noise.

If you compare the synchromesh on the left to the one on the right you can see the stop tab has broken off. This tab locates within the hub with a small amount of play and allows the gear to match the hub speed and stops the synchromesh simply rotating with the gear once it has gripped. The tabs had made their way around the gearbox luckily not coming into contact with gears and bearings. The synchromesh on gears 3, 4, 5 and 6 are all of the same design and same part number. This part has thus superseded and a new design of synchro replaces this in order to prevent the issue happening again. We would recommend changing all four of the old design of synchro if the transmission is removed to prevent costly repairs at a later date.


Models affected

Kia Sportage | 1700cc |

Kia Ceed | 1400cc 1600cc |

Kia Rio | 1400cc 1600cc |

Kia Rio | 1400cc |

Kia Venga | 1400cc 1600cc |

Hyundai I30 | 1400cc 1600cc |

Hyundai IX35 | 1700cc |

Hyundai Tucson | 1700cc |


Contact Eco Torque Today

Tel: 01462 835335 Email:

Eco Torque Ltd

Unit 1A Portland Industrial Estate

Hitchin Road


United Kingdom

SG15 6SG

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