Gearbox problem, Stilo 1.8 ...

[steviewonder]

Hi guys, got a friend with a 2003 Stilo 1.8, recently it's started jumping out of 4th gear, the car has 42k on the clock and has been well looked after.

Does anyone have any ideas what it could be?

I read somewhere about a cable seizing causing this, could this be the case or it the GB goosed?

Cheers!