Truck vibrates/shakes when fuel tanks are low on fuel

Next to my seat i have 10mm wrench to adjusting ride height. I tryied low and high but still vibration. It does shake less when i adjust hight but i dont wanna have blown air bag because small 8 airbags on AG 200/400 doesnt lift much. But i keep it at OEM 6 1/8" for now
BTW all 8 airbags are new and big 1" supply hoses with leveling valve and splitter/dump valve
I had 04 Volvo for 10 years with 2M miles and i didnt mess with it this much like i do on this KW that i have for 18 months haha. Ride was good till i start upgrading old to newer design suspension. I should just left it alone but me i cant leave anything OEM

 

Top of rear axle to the bottom of frame

 

I have same pdf ag200/400 manual. But thanks anyway

 

My old AG200 threaded pins were bad, all 4, and i had adjusted ride height with them. Than when i installed AG400 torsion/sway bars riide height was 1" lower or 5 1/8. Im guessing of bad angle of old threaded pins since Y wishbone/torsion bars wasnt sitting on 90° in sway bars. After i installed AG400 i did try 5 1/8 ride height but than i adjusted to 6 1/8. In that time i didnt have any vibrations. Vibrations came a few months later
Both AG200 and AG400 are 52" so axle slant didnt change. AG400 sway bar bolted with buching right where AG200 was so i didnt have to change mounts that are welded to the axle

 

No. I havent mess with torque rods or change them. Bushings are in good shape without play. In future ill change them with Atro ones just bushings or trorque rods with bushings. They all have 1/2 spacer on my 99 T2000 that came with AG200 and also on my 00 T2000 part truck that i swap AG400 from