I would definitely use the Super UDT or the Amsoil equivalent if you are going to use the tractor when it's cold. -10F or colder. If you don't the HST filter can leak. My 3410 did it twice, dumping 5+ gal of hydro fluid each time. Both times were with UDT, temps below -20F and after warming the engine up.
Heating the engine WON'T heat the HST much at all. So, when heating the engine at 12-1500, use the clutch hold down. That will keep from building pressure in the HST. After the engine is warm, let the clutch in and see how much drag there is. Let it pump for a while (5-10 min) and then go.
Heating the engine WON'T heat the HST much at all. So, when heating the engine at 12-1500, use the clutch hold down. That will keep from building pressure in the HST. After the engine is warm, let the clutch in and see how much drag there is. Let it pump for a while (5-10 min) and then go.