I asked about this in my previous post -D6 8U w/Le Tourneau scraper, but I think it got lost. Did they have different trans ratios for dozer cats versus scraper cats. This D68U I am looking at seems high geared in 1st. I have been told that some D8's had high speed reverses, so was wondering if different ratios were optional.
Yes, there were a couple of transmission ratio options. (Answered sometime back so had the material on file). Someone else will need to answer your land planing question. The one parts diagram is kind of light, hope you can read it.