Personally I don't think using any sealant is a good idea. I think any modifications will void any future warranty claims. As long as the nut is tight on top of the unit I think it is pretty well weather-proofed.
Do you have it hooked up at home and out in the weather 24/7? Is it normally out in a lot of rain? You could us a plastic bag over it and use a rubber band to seal it around the cord.
Anyway, I don't think you should worry about a repeat water event. Nice to hear they took care of you....
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Lee & Kathy, and our alarm clock Jake!
2017 Starcraft Autumn Ridge 266RKS 50 amp.
2017 Toyota Tundra Crewmax 4x4, 10-1-2021