Chip, take smaller bites. You are trying to move too much material at one time. You would have no trouble doing the task with a 4 wheel drive,but with 2 wheel drive you are just going to have to make more passes and take less material. As far as getting unstuck using the FEL.......... You can't or you will ruin your manure forks. Just work a little less material at a time. Dont' let so much build up in the box an halt your forward momentum. Once you get too much in the box your 2 wheel drive tractor is not able to maintain enough traction to pull the weight of the material.