1997 reg, nissan micra. occurred suddenly when temporily parked to enter a gate: cannot engage any gears when engine is on; it is OK when the engine is off.
sounds like hydraulic system failure(possibly the clutch slave cylinder or clutch master cylinder needs replacing.if its not these then the clutch is gone ,get a good garage to look at it
howtomendit.com for free repair help, information and advice.
