well I asked a MB mechanic and he said it's not the gear box, it's the steering wheel U-joint which the bushings on it are worn out, hence when you turn the wheel, there's free play. He said he's fixed a few of them and the cost is about $350. another person said, it that's the case it shouldn't be that hard..... well I'm ordering a MB shop manul and see if I can do it myself for about $50