Bucking bronco FLD120

Well, went a couple years without having to ask much of everyone's knowledge when it comes to keeping my Freightliner on the road, mainly because I just drove the darned thing...and it just ran. This year some issues popped up and she is such a reliable old truck for me I decided to spend a pretty penny on fixing it up. Out of frame overhaul, front end rebuild, 5th wheel rebuild, new airbags, leveling valves, all sorts of things I replaced on this truck, and still some big problems persist. Thanks to everyone who takes the time to read these and even though I'm always thankful for every bit of advice, here's an initial THANK YOU! To anyone who wants to chime in. Problem is, starting this last December, did a rough job hauling dirt from an oilfield site that was very rough. Roughest roads I've taken my truck on so far, tried to be drive nice but these oilfield roads just kicked this truck in the teeth it seems. I noticed as soon as the day was done and I was back on smooth roads, it rode much rougher than before. It actually bucks your seat forwards and backwards every time you hit a bump, repeatedly. Like, every bump you feel several times, and you can see the hood bouncing repeatedly every bump. It beats the ever loving snot out of me to drive this truck now.
Things I have done:
*front end was worn in just about every way. Did kingpins, brand new springs, shackles, bushings, spring perches, pins, tie rod ends, connecting arm, wheel bearings, and brakes.
*replaced all shocks, cab and suspension. Upgraded them to Monroes, but they rode as bad as the old worn out ones. Every bump is felt 3-4 times. Took them off, switched back to Gabriels and it rode better, but still bucks the seat forwards and backwards.
*Had the truck 3 axle aligned
*checked cab mounts, they look a little cracked but I can't see any place where things are moving around, bolts are still tight. Cab track bar is tight as well.
*replaced leveling valves on suspension and cab. No change.
*rebuilt 5th wheel. With that tighter, it rides even rougher.
*new steer tires. BFGoodrich, same as I've always ran
Truck always rode fairly smooth until after that oilfield job!

1997 FLD120 Set back axle, Vin 770342. 40k drive axles with lockers
3406e Cat, 5EK. 18-speed. Approx 2.2 million miles, was over the road truck until the last 200k.

 

UPDATE.....Always first, a big THANK YOU to everyone who took time out of their days to give advice, especially as the busy season looms ahead! So....wound up needing a different trailer to start a new contract hauling compost, getting out of the rock game for a while. I had been pulling a 2016 Armor Lite lightweight steel end dump, pretty much the same as the Lufkin I had for a couple years, spring ride. This is going to sound incredibly dumb and obvious, but everything about how this truck was riding was in that darned trailer..... I got rid of it and switched to a Travis double wall aluminum with air ride....instant end to the violence that was my cab....I can't believe the difference between spring ride and air ride as far as end dumps go. We have two live bottoms, one an old red river with spring ride and one Aulick with air, and both seem to ride about the same, but not the case with an end dump! THANKS AGAIN to all for your knowledge!