A gearbox repair kit is a specialized kit used for repairing automotive gearboxes. It typically includes easily damaged components such as seals, gaskets, filter elements, and O-rings. It is suitable for repair in the case of gearbox oil leakage, abnormal gear shifting, and internal wear.

Functions of a gearbox repair kit:

1. Repair oil leakage  

Replace aged or damaged seals and gaskets to prevent gearbox fluid leakage. 

2. Restore gear shifting performance  

Replace worn friction plates, valve body seals, and other components to improve gear shifting smoothness and response speed.  

3. Extend service life of gearbox  

By replacing easily damaged components, internal wear is reduced, thus extending the service life of the gearbox.  

4. Save cost  

Compared to replacing the entire gearbox or assembly, the repair kit leads to lower costs and is suitable for repairing minor damages.

Main components in a gearbox repair kit:

Seals/gaskets: They are used for sealing parts like housing, valve body, and oil sump to prevent oil leakage.

O-rings: They are used for sealing connections such as those for oil pipes, sensors, and solenoid valves.

Friction plates/clutch plates: These are key components used to transmit power in automatic gearboxes.

Filter elements: They filter impurities in the gearbox oil to keep the oil clean.

Valve body repair kit: It includes sealing rings, springs, valve cores, and other components inside a valve body.

Oil sump gaskets: They are used for sealing between the oil sump and the gearbox housing.

Bearings/bushings: They are used to support rotating components and reduce friction.

Supplementary oil (for some kits only): It is used to refill gearbox oil. 

A gearbox repair kit is suitable for solving the following problems:

Gearbox oil leakage: There are obvious oil stains on the housing or connections.

Abnormal gear shifting: There is a sense of jerking, delay, slipping, or failed response during gear shifting.

Abnormal noise: Metal friction or impact sound is generated in the gearbox.

Oil contamination: The gearbox oil turns black or has metal debris or a burnt smell.

If there are problems such as oil leakage or abnormal gear shifting in the gearbox, the gearbox should be checked and repaired it in a timely manner to prevent occurrence of more serious failures. After maintenance, road test and oil pressure test are required to ensure normal operation.