Owner Operator Insurance Question- Help!

I currently have a 04 F450 and 17 Gooseneck trailer insured both with physical damage and standard $1,000,000 auto liability comp/collision.
My rate is good with this equipment but when I tried to replace the Ford with a 15 Ram 3500 my insurance premium literally doubled. Could I keep the Ford and gooseneck under that policy pay 2 insurances and use a different company to insure the Ram on its own physical damage? Ram will have its own insurance cab card as well but my concern is with DOT, are they particularly looking for the VIN to be on the same policy or as long as the COMPANY has its million liability you’re good?