Not sure what is causing the issue. So I posted it here. When I put a heavy load on my 2008 F450 Lariat, 4x4 6.4, She bucks real bad. It only seems to happen when I am just starting out or going real slow. It stops as I speed up or get into the throttle. I am towing a goose neck dump trailer. It does in very minor when empty. When she is loaded (about 7 ton total) it is almost impossible to get going real real bad if going slow up a hill. Once I get on the road it settles down. I have done the DPF and EGR delete and have a gearbox Z tuner installed. All done by a very well respected Ford mechanic. I had the tranny flushed about 1000 miles ago. Truck had 141,000 miles on it. It also started bucking a little when coming to a stop. I am new to towing with a goose neck so a I am not sure what is normal or not. I am also thinking the shocks are in need of replacement, front tires are starting check on me. Any input you guys could give would be greatly appreciated.