It sounds like it could be the torque converter but it's hard to figure something like that out. You may need to take it to a good tranny shop and have them look at it. I've had torque converters out on Mercedes cars and they all sounded like they could have something loose in them but there was nothing wrong with them. I'm wondering if the guy torqued the torque converter bolts to the flywheel correctly. I had a car long time ago that had a knock when idling and would make a terrible sound after revving the engine. It turned out to be simply loose torque converter bolts.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012