I would say that it dramatically depends on your specific drain field design, and your specific soil type.
When I asked the septic guy who inspected our system during the home buying process, he started off saying sure thing. Until I told him my tractor weighed 7k lbs, in which he emphatically said "NO!".
He was thinking I meant a riding mower (which is fine) until I described to him what I had and how much it weighed.
Some septic fields may be deeper, or soil types different enough that it wouldn't be a problem to drive the same tractor at a different site.
At our old house, it was not a problem. House was much older, septic field was different and much deeper.
I wouldn't let a few random guys across the internet tell you if it's safe or not.
Just my 2 cents worth.