I have a client who has had considerable damage to his back lawn due to his dogs playing in it and tearing it up. I will describe this as about 50% decent grass with the other 50% being a mixture of torn up grass and dirt. He originally was inquiring about over seeding (which I have never done before). I have, however, installed many new lawns. I have always used a tiller on the back of my compact tractor because it leaves an awesome base for new seed (provided there is decent soil). My suggestion to him was to essentially start over. I don't have a good feeling about trying to over seed a lawn with this much damage, and trying to get new seeds to grow in already compacted soil. My only concern is how well a high rpm tiller will chew up the existing sod already in the lawn. I know there is a HUGE difference in the way the 3 point tiller will chew up ground as compared to a walk behind tiller. The tines on the 3 point tiller spin so fast you can't see them, where as our rear tine walk behind tiller's tines spin so slow you can practically count the revolutions of the tines. Has anyone ever tilled up sod with a 3 point tiller with any success? I won't mind raking up some areas that may have excessive clumps, but I would like to know what I am getting myself into before I prepare the quote. Thanks for your advice.