I had an oil leave develop at about the same time as you. I happen to have been at the FMCA rally and the manufacture was there. I was led to believe they know about the leak developing and had it repaired for me at no charge. There was no questioning if I had warranty or not. It was a major job. They shipped parts to dealer where I was travelling to. The generator has to be removed completely. I might suggest you give Guardian a call to discuss this.
2004 Newmar, Mountain Aire 40ft, DP
Langley, BC, Canada, 2011 GMC Sierra Pick UP is our toad.