I have a 2000 4600 HST that is sluggish when changing directions from forward to reverse and visversa. I have had the tractor about 4 months and up until the last week or two it has worked fine. It does't seem to be as bad when it is cold. I took it to the dealer a week ago and they changed the fluid and filter and said the couldn't get it to act up. I drove it back to my shop about a quarter mile away, put a blade on it started blading and it seemed to be working normal. About 5 to 10 minutes later and several times of changing directions it started acting up again. When it happens and you chang directions, there is a lag of about 3 to 4 seconds before the tractor starts moving in the opposite direction. Any Ideas? Please