Box Automatic Changes of 406 2.0 HDI 2001

Good morning. I have a problem with my automatic gearbox. It's from a 2001 Peugeot 406 2.0 HDI. I believe the model is AL4. The problem occurs when the car reaches 90°C (194°F). At that point, when I stop the car, for example at a traffic light, and then start driving again, it jerks very noticeably. I also notice that when I'm pressing the accelerator pedal, almost coming to a complete stop, there's a slight jolt, as if the car were braking suddenly or slipping out of gear, and then when I start driving again, there's the same jolt, even when the engine is warm. I should mention that we've already replaced the valve body, and it's still doing it. Any help would be greatly appreciated. Thank you very much.