I have a 2000 323ci with auto transmission and 91000Km and i'm having some transmission problem with it.The transmission was working perfect...i just parked the car in front of the house one night in perfect condition and the next day when i started to get to work the transmission started to change gears like crazy.When it goes from first to second and from second to third it jerks i can feel like a bump allmost moving the car forward its like its hitting something.I never felt anything before it was working fine.The car sits outside in the cold i dont know if that has anything to do with it.I took it to bmw,they put it on the computers and didn't see anything so they called their tech support and they said that there is an oil pressure problem and the oil pump in the transmission needs to be changed.There are no warning lights showing in the dash.Can you guys tell me what you think if any of you had a problem like this before?Thanks.