Welcome to the Orange Club!
As one or two have already mentioned; stick to the Kubota hydraulic oil. A quart of something else isn't going to do harm, but for a full on change it's worth sticking to factory recommendations. Wise choice to go ahead with an engine oil change. It's inexpensive and good insurance. Diesel oil does go black pretty fast but you'll know where you stand with a fresh fill. I'd recommend a good diesel fuel additive- Amsoil, Howes, Standyne....take your pick. The important thing is to use a demulsifier to let the water separator do its job. Speaking of fuel- if you can find an off road diesel pump it'll save you the road tax on fuel. Off road fuel here is $0.75 cheaper. Not sure what Maine taxes are.
Enjoy the machine!
As one or two have already mentioned; stick to the Kubota hydraulic oil. A quart of something else isn't going to do harm, but for a full on change it's worth sticking to factory recommendations. Wise choice to go ahead with an engine oil change. It's inexpensive and good insurance. Diesel oil does go black pretty fast but you'll know where you stand with a fresh fill. I'd recommend a good diesel fuel additive- Amsoil, Howes, Standyne....take your pick. The important thing is to use a demulsifier to let the water separator do its job. Speaking of fuel- if you can find an off road diesel pump it'll save you the road tax on fuel. Off road fuel here is $0.75 cheaper. Not sure what Maine taxes are.
Enjoy the machine!