Ok I've got a MX6 and here is my advice. You want your cutter to lower in the front than in the back. I've got my MX6 set in the hole next to last. I would move your wheel thing another hole to raise up the rear of the mower and lower your front with your 3pt hitch. If your cutter is high in front and low in back then you have unmowed grass/stobs pushing up on your pan then they contact the dull part of the blade and then they hit the cutting edge as your mower goes over them. Best to have it low in front and high in back.
The rear wheel and spindle really like the grease on my MX6. The rear wheel axle always takes plenty of grease so watch that and grease often back there.
The MX series gear box doesn't have a drain plug. You have to siphon out the gear oil when you change it. I changed mine about at ten hours use. I used about 4 of the little air tubing that you use for aquarium air pumps. Took it about a hour but I think I got all of it out. If you use heavier tubing I think you can't get to the bottom of the gearbox nearly as well as the smaller more flexible tubes. Some MX owners flip the mower upside down to drain the gear box oil out the top fill hole.
I used JD gear oil but next change I might go to a synthetic oil......just for kicks.
When I grease the u joints on the pto shaft I find it easier to just remove the shaft from the gearbox of the mower and grease it and then re-attach it to the mower. It is a hard zerk to get to to grease unless you do that.
Don't sharpen the blades if your cutting brush! It leaves the stumps sharp with a danger of a tire puncture.
My MX6 cuts nice and so far hasn't had any of the issues with the gear box some have had with the older 55 HP gearbox. Yours and mine both have the newer 75 HP rated gearbox. Good luck and they are a pretty snazzy looking cutter.
