40 degrees is going to be hard to keep it from sliding down the hill. You can minimize the angle by rolling the FEL bucket full down and then jacking up the front of the tractor as high as it will raise. Watch your oil pressure, as long as you have good oil pressure it will get lubrication.
Have you actually measured the angle, 40 degrees is quite steep. Don't get sideways on that hill what ever you do as it is near roll over steepness.
I don't think my
B26 would back up a 40 degree slope nor hold on the slope with the outriggers. I dug in a sprinkler ditch once on a side slope or 20 degrees and it kept sliding down hill. Down hill stabilizer was all the way down just to level the tractor and everytime I raised it, the tractor slide about 6" downhill.
BE CAREFUL IF YOU TRY THE 40 DEGREE.