Every time the car is coming to a full stop the car jerks! its not so bad when i go really slow and let the car almost stop on its own but when im going fast and hit the brakes to a full stop it jerks even more obvious. Mean time, I also notice, in steptronic mode, when the car is not moving and I downshift from M2 to M1, the car jerks with a small bang, so my question here is this a common problem? has it happened to you? and how did you fix it?

i appreciate all your help

 

What year is your car? And what kind of 5 do you have?
My 04 545 somewhat had the same problem that you're talking about. It would thump/thud cruising around 35MPH.

 

my car is 04 530i build 07/04 m54 engine, i have very smooth shifting while driving its only when im stopping

 

This shaking/jerking sounds a bit like the control arm bushing problem seen on the 3 series - when the bushings wear out, the wheel can move a couple of inches during breaking, usually in rapid succession - there are other suspension problems which can have similar symptoms, so you'll need to get the car to a good repair shop to get things figured out.

The transmission issue can have other symptoms, or it could be a source of a hard jerk when shifting gears.

 

See! i was thinking the same thing but then why would it jerk when the car is NOT moving and I downshift from M2 to M1??

 

I have a 545i and experience the same thing, it's the transmission shifting down when you come to a stop, most likely from 2nd to 1st gear. very annoying, never felt anything like it even in the cheapest cars.
That jerkiness feeling should not be there in manual mode though because you are manually shifting it to M1 when you stop.

 

Even if you go to manual mode it doesn't shift as a manual transmission! its still shifting electronically it's not the same as a manual transmission, I don't know what it is but i really wanna get to the bottom of it.

 

Sound like an issue with the gearbox.
Easy solution; Have the gearbox learning reset.
Hard and expensive solution, replace the mechatronic.

Has the gearbox fluid ever been replaced?

 

Software is not latest, check with the dealer if you have any updates for tranny software.

 

[font="'Comic Sans MS"]this is a very common problem known as the "transmission slam", search for it and you'll find out loads of information.[/font]