As the UK's leading supplier of replacement commercial vehicle transmissions parts, H L Smith have a wealth of information about parts and maintenance of your commercial vehicles.

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Problem - jumping out of gear (the gear lever moves from its engaged position).  What should I check?

Remove linkage from gearbox and select gear manually . If the gearbox remains in gear, check the following:
1. Are linkages, tie bars and ball joints worn. Are they free from any obstruction?.
2. Are the gaiters intact – debris from worn gaiters can jam the linkage.
3. Are the cab or engine mounts worn? Cab/engine movement can jam the linkage and stop it moving freely.
4. If the gearbox has been removed, has it been reinstalled to its original settings.?
5. If fitted, are linkage dampers or springs worn or broken? Worn or broken dampers can allow excessive movement of the gear stick causing a jump-out situation.
6. If fitted, are external detent plungers and springs worn or damaged and are they set correctly?

For more of Andy's advice about Gearbox problems, visit our Technical Help line page

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