Robert,
I really think that the tractor is putting out about the 75 HP it is rated for, I am just trying to disc in what is really too high a gear, as to get as much done in the limited time I have to get it done. If I am in any of the A range gears it is fine, and if I am in B 1 or 2 the tractor never loads up, but I have lately been running in B3, B4, and even occasionally C1 and C2 on the third and fourth passes over the ground. I know that this is really pushing it, but I have to get the discing done pretty quick so that I can get the grass planted before the dry season. I think that it is also the really agressive gang angle I am using too, since I did not notice it loading up before I changed it, even in C1 and C2. Please do not try this at home, not that I am a trained professional or anything, I would just hate to see someone else ruin their disc by hitting any rocks, pipes, etc. The area I am discing at this rapid pace is very flat, smooth, and there are not any rocks to be found anywhere.