2000 impala, 3400. No check engine light is on. When I am at a stop, and take off quickly, the car chugs badly. It won't take off right away. It doesn't even feel like the trans is slipping per say. It makes a loud noise too. It "chugs" two or three times before it goes, which is only about 1.5 seconds. After second gear, it shifts like a champ. I had the trans pan cleaned and filter replaced. It had a lot of metal in the fluid. It still chugs. Any help would be appreciated. Thank you.