Here is my 743 after hours of work pulling blown engine, scraping, vacuuming crud over and over again, and degreasing. debris mixes with oil residue and gets jammed between eng and the yellow plate, which I think is the rear of the chain case. My lines were all buried in the grunge. That debris traps moisture, and yes, I had the pinhole leaks as mentioned, in 2 hard lines. Since I was in this far, changed all the horizontal hard lines (a local diesel shop made new ones on a pipe bending machine $300). if you get this deep, perfect time to change spool valve seals. A local hydr fitting shop had the "T" fittings which were NLA at bobcat (no longer available). Engine slides right out after the 4 motor vibration mounts were removed , and the other stuff (exhaust, fuel line, wiring, fuel shut off cable). I made a wooden platform the exact height of the engine bay floor, and slid the engine out onto it. And yes, I learned most of this from this forum and thanks to forum-veterans like Tazza, bridgebldr, and others. Hope this helps .