Automatic Transmission Torque Converter problems of the 2004 BMW X3

My transmission/vehicle at 40mph on flat or slight decent will jerk back and forth when you take your foot off the accelerator. BMW has replaced the torque converter, transmission, traction unit, abs sensor unit, to say this is normal with the 2. 5 engine. I find it surprising that this is the case. Now, since the repair my rear suspension makes noises, like there is a problem. They have tightened it up, but it is back to the same problem. I see there is pending lawsuits over the rear suspension of certain BMW vehicles. Needless to say, nothing is fixed and now new problems have occurred. The local BMW dealer has been really good about this, it seems they are under advice from BMW.