2009 Grand Voyager 4th Gear not in Syncro
 

Hi All,
Every now and again when I'm driving my 2009 2.8CRD Grand Voyager is drops all the gears leaving me with only 1st gear. If I pull over, turn off the engine and restart the car it will then drive as normal, changing gears as it should. Lately it is doing it more regularly and yesterday it did it again and the engine management light came on. I put a code reader on it and it showed the following codes: P0734, P083B, C0100. On one of the codes it said that 4th gear wasn't syncronised, any ideas what might be causing this please ?