I'm not sure if the d-7 & d-8's were set up the same. I worked for a mechanical contractor that had an older d-7. The drum & clutch were on the back of the dozer with a long tiller handle extending foward to the operater. There was no "float" detent, you adjusted your pressure on the tiller to raise & lower the cable operated blade. Float was a constant juggling act of applying clutch pressure & releasing it. If you just let go, the blade SLAMMED to the ground. How in the hell operaters graded with this setup is beyond me. Remember, humans have 2 arms & 2 legs. So, 2 steering brakes for the legs, 2 steering clutches for the arms (positioned between your legs), a clutch tiller for the blade (located kinda high by your right shoulder), uuhhhh i'm outta appendages.....it had the hand crank pony motor, took forever to build enough heat in the big diesel to fire it in winter. The two shared common cooling & oil systems, that little pony motor just didn't generate much heat to warm the BIG engine. This was before glow plugs, so some heat was needed. The pony motor had a 2 speed tranny, you NEEDED low gear to get the diesel rotating before you hit high gear to fire it off! Restringing the blade cable was fun too, try running a 5/8" cable through 20' of 2" tube clogged with 50+ years of dirt & grease, then around a pair of 3 sheave blocks at the front at the blade. You guys that only know hydraulics & computer "return to level" systems don't know what your missing!!!!