Prius II jerks

Hello! I got a Prius II in August, running from 2008, 85,000 km. Unfortunately, he has the habit of jerking a little bit with every start of the burner. This feels like he slows down slightly when the engine is turned on and then accelerates again when the engine starts. In other forums, the change of the gear oil is recommended, but this has absolutely no effect. The jerking occurs even with constant speed. It feels a little as if the whole drive has too much play. Even if I drive electrically backwards from my garage, there is a jerk when the brake is released, which is accompanied by a clearly audible “crack”. Maybe someone knows the problem. With previous vehicles in my possession like the Smart Fortwo or the VW Lupo 3L TDI helped with similar sufferings an update of the clutch electronics. But as far as I know, the Prius has no… Greetings!