The operator and maintenance manual for your tractor is readily available, it is a Dept of the Army Technical Manual, TM-5-2410-229-12.
However, the Dept of the Army Service Manual for your D6B seems to be quite elusive. There used to be a big list of TM's available online, but it seems to have disappeared.
The following site may be able to assist in your search for any Dept of the Army Service Manual - but it's entirely possible that the military merely used the regular, civilian Caterpillar Service Manual.
https://guides.loc.gov/us-army-technical-manuals/obtaining-copies
Caterpillar commenced production of their own design angle blades and straight blades in 1947, but other brands/makes of blades were always available as an owner choice by tractor buyers.
Cable controls were chosen as the preferred method of implement control during the early stages of WW2, and this preference was driven by the insistence of Robert G LeTourneau, that cable controls were superior in every way to hydraulic controls.
Of course, in 1942, R.G. Le Tourneau was right - because the hydraulic systems of that era were low pressure, slow, and seals were manufactured from organic materials such as leather.
However, major technical and product developments during WW2 saw the introduction of nylon, teflon and other synthetic materials that could resist high pressures, high temperatures, and provide long-wearing characteristics, saw hydraulic and attachment manufacturers move rapidly into introducing higher operating pressures and high quality seals, which allowed for faster hydraulic speeds and performance, that gradually drove cable control systems out of business by the late 1950's.
However, old habits die hard and the military obviously still thought in the 1950's, that cable controls were superior. The fact that minimal amounts of oil were needed for cable control was advantageous in some respects, and it removed the problem of ensuring the correct oil was in the right location, and that operators couldn't become confused over oil types to use.