It has been a while but IIRC the manual calls to change the hydraulic filter (just the filter not the oil) and change engine oil and filter at 50 hours. That was all the oil changing required for mine. Tightening of all bolts on the FEL mounts, wheel rims etc is required also. Especially look at the two bolts behind the fuel tank as both of those were several rounds loose while the rest were pretty tight. You can only use a combination wrench there due to minimal clearance so I can see why they might have been loose, plus you can barely see them at all.
Congratulation on your purchase. I know you will like it.
I had trouble with the front wheel final drive bolts loosening off especially on the left side. After the second tightening, I bought all new Gr 10 bolts and some Swedish built 2 piece lock washers(available at Fastenal-can never remember the name of them) and blue Loctite. Replaced them all, with the new washers and Loctite and they have not loosened again.
Great tractor with lots of engine Horsepower, much more power than the tractors weight can handle. You really need to fill those rear tires and maybe even get some rear cast iron wheel weights for optimum traction. It wont pull very much in 2 wheel drive with the FEL on because it is just too light in the rear end without something heavy on the rear. I filled the FEL with oak wood once and in 2 WD it wouldn't back up a slight incline before I filled the tires with water and I had a box blade on the rear at the time. One really needs about 1000# of wheel weights plus tire ballast when using ground engaging implements.
