raise the floor cover.
remove both belt covers (left and right)
remove drive shaft (17mm bolt)-slide the shaft back a couple inches.
remove the tensioner spring. It's really stiff so you have been warned
remove the RIGHT side gearbox "stay" (bracket). 3/4" socket for all 4 of the bolts. ONLY the right side (as you are sitting on the mower). Don't touch the other side.
Remove old belt
install new belt
reinstall the bracket
reinstall spring with lots of newly invented words. I use a wire clothes hanger with a loop on each end, one end on the spring and the other with a screwdriver stuck through it for a handle.
reinstall drive shaft (17mm pinch bolt)
reinstall deck belt covers.
CHECK THE GEARBOX FLUID.
drop the floor cover.
