You absolutely can do it yourself with those pieces of equipment. If you haven't already found a D3, try to find one with a 6-way blade, as it really increases the versatility.
While you are at it, I would put a wide deep breach in the old dam and install a good standpipe with an antiseep collar. When you rebuild the dam, do it in 2-4 inch layers of moist clay that are well compacted. If you've got ag tires on the backhoe or tractor, they will usually do a better job of compacting than the dozer tracks, just because of the pressure per square inch from the bar treads.
Before you drive anything into the body of the old pond, make sure it is dry and solid. Old ponds have a way of swallowing heavy equipment -- I speak from experience. Using the backhoe and dump truck is probably the safest and fastest way of removing the old muck, unless you can do it with the tractor loader.
Make sure you put in a good emergency spillway. It will keep the dam from breaching again.
Good luck,
Ken
