Just to give as much info as possible here. The same hitch has been used on 4 trucks, two diesels with the 10-speed allison and two gas HD's one with the 6-speed and the current one with the 10-speed allison.
3 of the trucks had the factory puck system, one I installed bed rails and bought new legs for the hitch but used the same head.
Truck # 1 was a gas engine 6-speed 2500 hd crew cab short bed 4x4 with factory puck system. Installed timbrens to correct any driveline angle issues. Had a new torque converter installed as well as transmission pump. Assuming it was the truck... I traded for truck number 2.
Truck # 2 was a duramax/allison crew cab short bed 4x4 with bed rails but same hitch head with new legs.
Truck # 3 was a duramax/allison 3500hd crew cab long bed SRW 4x4 with factory puck system and reused original legs on original hitch.
Truck # 4 is a gas/allison 3500 SRW short bed crew 4x4 with factory puck system same hitch and legs. When I installed the hitch in this truck I made sure all bolts were tight and have the feet/cleats locked to the bed tighter than I ever have. (this elliminated any slop in the hitch when starting or braking and I have zero "clunking" slop.
My first thought was driveline shudder which is why I have installed timbren SES on all of the trucks and the "tugging" is there with our without them so I've pretty much ruled out driveline shudder since the timbrens keep the truck pretty high in the rear. But I enjoy the stability they provide so I've kept them on each truck.
I know 4 trucks is a lot in a couple years... And no, I'm not wealthy but I work at a chevrolet dealer so I've been able to play my cards right in regard to the flucuating market and trade values. I have been fortunate enough to be able to trade often without really costing me any real money.
The trailer brakes seem to function as they should and there's nothing I can see that would indicate a worn or out of shape drum, though the drums and bearings are about the onluy thing I haven't pulled apart.
I just had all four wheels off when installing new tires and all were retorqued. Again, same tugging as before with the old tires.
The unit has the "road armor" suspension. Possibly the axles are bouncing or hopping when being pulled at certain frequencies?
I'm honestly boggled. I've learned to live with it but assume something is causing it and may have bigger consequences later on down the line if I can't address it.
