What you're looking for is a "universal tractor fluid" or "hydraulic/transmission fluid" or something similar to that. It will say somewhere on the container that it is compatible with, or meets specifications for a whole list of things. Look for JD303 (John Deere 303), J20A,B,C,D or IH Hy-tran. There are some other specs that are equivalent, but those should usually be there. I know some people have run ATF in their machines, and say it works better in the cold, but I'm ignorant about the comparitive chemistries of UTF to ATF. Also, it never gets cold around here, really. I'm more concerned with hot weather protection than cold weather.
This is available at Napa, they have a house brand that is equivalent. Any tractor dealer will have it, too.
I don't know how much your YM1700 will take, but it will be around 5 gallons. Be careful when you open up the drain plug, in other words! Have a bucket and a pan ready to catch it all if you're changing it out. Make sure to clean the screen as well.
Check to make sure the 10W-40 is rated for diesel engines. The bottles should say API CJ-4 rated or something. API CI-4 or CI-4 plus is good too (some may argue better.) 15W40 is the standard conventional diesel oil. It should be available everywhere. Wal-Mart's Supertech brand is actually about as good as anything else, and is usually cheaper. Before the 5W40 was so close to conventional oil in price, I used 15W40 from whomever had it on sale in all the things I own.