Gear Jumps during shifting BMW525i

[Lakbir]

Dear All,I need some advice.I just got a recond BMW525i Japanese spec a 2004 model which runs pretty well on straight roads. But when its coming to an uphill or downhill, the gear doesn't change in normal circumstances, it drags a while and when it changes, there is a jump feeling, it means that the change is not smooth just like changing a bike's gear without engaging its clutch.I have the dealers warranty until middle of next month, i have taken to their authorized BMW workshop but they said that they couldn't detact anything wrong.Anyone who has come across this problem, pls write to me.Thanks brothersJay