Thank you for your question.
I am sorry you are having a problem with the tiller. According to the parts list for your tiller the gear case came with grease called plastilub. If the seal was leaking, I suspect very little grease came out of it. In order to add grease to the gear case you have to take the gear case apart. Do to the small amount I think that would have leaked I do not think it is worth the trouble to add grease. You could drill a hole in the gear case and add a grease zerk. Then you can add grease without taking the unit apart. If you do this make, sure you drill a hole in an area that is not close to any of the gears.
I hope this is helpful. Please let me know if you need further assistance.
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