I'm interested in knowing exactly what is on the back end of the b model of the 42006 Excavator? In the description on the S@H site it says you can put a dozer blade on front, but all I can see is the axles sticking out the front, and the mechanism on the back makes me scratch my head as to what it is. To compare the 8275, that set had a ripper on the back but this odd looking rear end comes out at an angle. I was looking to possibly buy a 2nd copy for the b model, but I am tossed up about it...