I don't know your machine but I had a 225 gas skid that did that. I jacked it up and adjusted the steering so the wheels did not turn. After that it still did the same thing. I found out that the clamp on the left side transmission shaft was loose. It widened the key way. I had to take the key way from 3/16" to 1/4" with a file. This was on the clamp. put new bolt in it and tightened it up. Had to reset the steering but it worked great from then on. Just something to check. Good luck.