Long Time Trucker First time problem.

Ok I have an issue that I never ran into before.
2016 Freightliner Cascadia Day Cab. it is only 2 weeks old.


I am running a Cobra 29 Harley Edition Radio That DTB in Carlisle, Pa has made sure that it was good.
I am using 18' of Wilson Coax
Mirror Mount (Made by Wilson)
Wilson T-2000 Antenna.

Here is where the issue lies. I can not get the SWR down below 2.5 All equipment used is Brand new and swapped back and forth with different coax and different antenna used multiple meters to check SWR.
A ground is run from the frame to the mount. I have a ground every where I check. if I have the door cracked just so it rests against the hook not closed but not open just pushed shut. My SWR will remain at 1.4. the minute that I close the door the SWR proceed to go back up. if I open the door they go up. But I can not leave the door unlatched while driving down the road. And the COAX is NOT run thru the door. it is run through the firewall. I have spent approximately 30 total hours hooking things back up and trying different things. and have now exhausted every avenue of my limited knowledge with no success. I can receive a lot but I can not transmit more than two miles without my transmission ending dead. I have for 20 years used the Wilson antenna line with not one issue on getting the SWR set to where I needed. But now at this point I am out of time and options. Can someone please help as I am at my witts end.
No I can not take the truck to a cb shop as I do not own the truck and I never run by a trusted CB shop and I am paid hourly so when I am in the truck I am getting paid. So I can not stop while in the truck. All my testing has been done in the yard on my own time.
No I can not drill anything as it is a leased truck and my boss would flip. It is his equipment
And during testing. I took a Wilson magnet mount antenna placed it on the frame behind the catwalk. the SWR were at 1.2 with a magnet mount placed on the rear frame. Which since I haul a trailer that sure wont work it was just a test to see if the SWR would be low Behind the cab with a magnet mount on the frame.

 

I have a ground strap run directly from the base of the mount directly to a clean spot on the frame and I get a continuous ground running directly from the mount to the frame and if I check the ground it all appears to be continuous.

 

I have now used shorter coax, different mirror mounts, ran the step ground per say from mount to hinge then other side of hinge to metal and so on, I also have tried multiple antenna right down to a 6' shipshooter. And i have attempted different combinations of each. Nothing has worked. I did for the time being find the issue with the two dual upper antenna. Freightliner had the radio and cb inputs reversed on the box behind the instrument cluster. So at least with those two for now I was able to get a setting of 1=1.9 20=1.4 40=1.2 those are the best results that I can achieve with the dual system after painstakingly tuning the antenna. Now I am still trying to find the major issue with the mirror mounts.