I was using my bobcat 642 to move gravel, I was going up a grade on a right-of-way when it stopped. Cranking it over it had on sign of life and I was then blocking traffic. I hocked another piece of equipment to it and drug it 50ft to get off the road. Later I found coil wire had fell off but now it will not crank over. When I pulled it 50ft up the grade I then used the starter to drive the pump to back the unit back off the road, it cranked a couple of times then locked up and then had to be pushed off the road, where it still sets. I put a new battery on it and the fan belt moved about an inch. I took the starter off but it was good, I pulled the spark plugs still nothing.. What damage could I have done by pulling without opening the relieft valve?