I have a ck30hst with right at 30 hours. I finally had a crew finish putting in a pond and it is now time to play. I have noticed on occassion my tractor will not move when trying to push or pull a load. Yesterday I put my tractor in low, 4x4, at 2500rpm and tried to push a few small stumps (8"-10" diameter)up into the pile. These stumps/trunks can't weigh more than a couple hundred pounds tops and they were already removed by trackhoe so they are not still buried. At any rate I was on fresh not even packed dirt and it just wouldn't spin a tire. I have R4s as well.