Update on '84 300 D turbo. Ran the Trans x for a week or so and then changed the oil and filter (Mobil DexronIII) Also changed the main vacuum line as I broke it when trying to remove a tube (very brittle), The fluid in the pan was a little dark. There was no metal in the pan. Transmission shifts very nicely now. I am not someone who believes in snake oil but... Trans x worked for me. Best to all. Tim