I bought this 856 last fall. When I looked at it before buying it I ran it around the lot and up and down the road up hill down hill, brought it to its knees with the brakes in both low and high several times. The only thing I noticed was a hesitation when shifting from low to high. When i got it home i did a complete service, new oil and filters all around. When I finally got a chance to try it out on a disk all was well at the start, still had the hesitation but nothing that concerned me a whole lot. Then after it got warm, the hesitation got worse and It started slipping when I pulled the lever back to low. To my way of thinking the t/a is good, if it was bad it would slip all the time not just when warm right? Im thinkinking it something in the valve. Clutch is adjusted correctly, light goes out right before tractor starts moving. Any help is appreciated.