Well, more of an annoyance. When I step on the gas and the car downshifts, revving up to the 6k mark... shift up, down(trying to decide between previous or next gear)... kinda wavering. It only happens when I put the petal to the floor and hit the kick-down switch, causing the rpms to hit top-end before shifting. Any ideas on what may cause this, as well as a fix? When driving otherwise it shifts smooth, no jerking or slipping... I know on some cars the auto trannies are vacuum assisted for the shifting - is that true on Bimmers (btw: I've got an '86 E23 L7 - 260k+)?