Warranties be damned..!! Frame warranties are like sledge hammer warranties. If it broke, YOU must have done something wrong, not us..!! Mounting your genny at the rear makes sense and can be accomplished. I did the mod on my last 5th wheel and it worked fine. I am a certified weldor and did the mod myself. First brace the square tube bumper with 3"X3"X1/4" (minimum) angle from frame rail to frame rail. Then gussett this angle brace to each of the main frame rails with at least 12" gussetts with 100% weld. Add a crossmember forward of the bumper between the main frame rails. Then mount a universal receiver hitch to this beefed bumper and new cross member. Then use a cargo platform (HitchHaul) made for receiver hitches to place generator, some leveling blocks, etc. Any competent welding shop should be able to do this for you. Check GVW ratings and present weight to be sure you stay within reasonable maximums. Wish I had pics of my mod for you but I don't.