I've got about 480 more hours to put on my mower deck until the first oil change, but since I put it up vertically on wheels for the winter it leaked quite a bit before I got it plugged so I'm assuming I may have to top off the gear box in the spring. The manual only says:The manual for my 1025R has similar verbage but also has an accompanying chart of oil weight vs temperature range. I'm wondering if I can use the same 80W-90 gear oil I have for my snow blower. I was thinking probably not considering the differing temperatures winter/summer and different PTO speeds of the attachments. I found this chart that makes it seem like mid summer mowing would be pushing it for 80W-90 but I might be okay if I'm just topping off and not doing a full oil change.Gear Oil
Use oil viscosity based on the expected air temperature range during the period between oil changes.
John Deere GL-5 Gear Lubricant is recommended.
Other oils may be used if they meet one or more of the following:
• API Service Classification GL-5.
• Military Specification MIL-L-2105D.
• Military Specification MIL-L-2105C.
• Military Specification MIL-L-2105B.
Oils meeting Military Specification MIL-L-10324A may be used as arctic oils.
This also makes me wonder about the tractor itself. I won't put enough hours a year on it change the oil more than once a year or so according to the maintenance intervals so where should my bias be for choosing oil weight considering that here in Iowa I may be moving snow when it is below 0 and mowing when it is over 100.