My D5 sticks like glue on a 30 degree slope, any direction. What you have to watch out for on slopes are rocks, pieces of wood, etc. which can cause the track to slip, especially sideways when working on a side slope. Don't put her in neutral on a steep slope and never forget about the big brake in the front! The easiest way to roll one is to fall off a pile of dirt you're pushing up by not paying enough attention. I came close to doing this a couple of times before I wised up. All that being said, never buy a dozer (or anything) without a ROPS.
