got an 863f, do it with the engine in. Need a couple of special tools to change it and a tensioner. If memory serves me they came with the belt, will have to buy the tensioner separately.I believe there is a u-tube video on the correct way to do it. The hardest part for me was getting those tamper-proof bolts off the cover. wound up cutting them off.I have the tensioner I found online, way cheaper than the $700.00 bobcat wanted. study the video, not that hard. Manuel says every 500hrs.