So I just had an electrician here checking out everything. He checked the transfer switch etc and found that it worked fine. He even connected disconnected the Genset power to the transfer switch and tried the shore power in its place. The transfer switch worked fine.
He traced it back to the very first junction box off the Genset and found that it was only getting 1.5 volts instead of 120 volts that it should.
He checked all the wiring and connections that he could and found no problems after the generator itself.
Oh well, at least we know the transfer switch is fine. Time to find a small engines:generator guy or a may have to break open my wallet and go to Cummins themselves $$$😟