It has been interesting hearing you compare the two tractors...We have a later model 17A with power steering and turbo - dry paper air cleaner, an old oil field Cat, as it has an 8 ft Balderson blade and Hyster D7D winch...We bought the machine in 76, have been completely through the rest of the tractor, but haven't done anything to the winch except extend the headache to raise the derrick of big rigs, and replace the brake band lining twice.
We also have a D6D LGP with turbo...It is interesting that Cat had a time making up its mind to keep the turbo in the D6C...I think with the 10K series they had the 3306 engine, but also thought they had a turbo, so I must have dreamed up part of the specs...The D6 has a cab, heat and air, power steering and the proverbial brake at the end of the steering handle stroke...Its a real spoiler after running the D7 for 35 years...The 7 is more nimble, and easier to see the winch, than the 6 is...Clearing, not a whole lot of difference in production, but pushing dirt the 6 wins out...not be a factor of 3 or more, but noticeably more production...AND FUEL...We had the 7 completely rebuilt, not all at the same time, but put a ton of money in it during the winter of 85, reman pony motor in it this fall...If there was a life threatening situation and we needed a Cat that would do the job no matter how cold, wet, or hot it was, the 7 is still more reliable that the 6...Forgot, but the 7 has hyd blade with the hyd group mounted behind the radiator...First appearance doesn't impress much as it looks like it would overheat with the hyd tank and controls in the way of air flow but the 7 won't get hot...ever...the 6 will heat up, we run distilled treated water in it during the summer months...Learned that trick with the 977L we had before the 6...the 6 has all new parts in both final drives, including the dead axles, torque converter is reman, only have engine and trans to go...I honestly believe the 7 will stay here longer than the 6...it is sure handy to load up quick to go pull out a combine or other machine and get back in time for dinner or supper...it has saved the day for us many a time...When I was a kid I always wanted a 7, to hear that torque load up, the tag says 1340 rpm I think, and it sounds like it is pulling down to 75 rpm at times if I don't react quick enough with the hyd lever.
someone mentioned the cable tractors had no down pressure on the blade...One of my biggest mistakes was trying to force the blade into the ground rather than keeping the cutting edge sharp...if I forced the blade down, it would hesitate then drop 8 inches quick, to quick to recover and made for not a very good road for the scrapers...I always try to carry at least part of the weight of the blade.
I guess we could say we still make a living with our old antiques.