I haven't checked the suspension, I'll have to crawl under it when I get a chance. I will say that Tuesday morning I had 5 new tires installed and had to jack it up myself since the shop didn't have a large enough jack or stands. I didn't notice anything weird with the suspension when I had the wheels off but I did trace the wires going to and from the brakes into the axle and didn't see any cracks or chafing any where on the wires, at least the visible portions.
The pinbox is the factory pinbox that came with the trailer, its a lippert frame so I assume a lippert pinbox but I honestly do not know for sure. I can check when I get home.
Current truck is a short bed with the factory puck system, hitch is about 3 inches behind the centerline of the rear axle. However my last truck was a 3500 duramax single rear wheel with the 8ft box. Same factory puck systema and hitch but the hitch was square with the rear axle. This truck also had the occaisional tugging at low speed acceleration but less noticeable... my theory is due to the additional mass of the diesel engine. But my point is the tugging was still there with the diesel and the long bed truck.
Would a possible brake malfunction in the trailer brakes cause this issue? As-in a defect in the shoes or drums or physical hardware?
On my first truck that had the torque converter replaced, the dealer tech rode with me to feel the tugging and we pulled the trailer with and without the connector plugged in to elliminate the brake controller. The tugging was there even without power to the trailer or braking system.
Honestly at a dead end with my trouble shooting ideas which is why I made the post.
The trailer has 8600 miles on it currently but has done this since new. Always assumed it was the truck or hitch. I have blown two factory chinese trail ride tires. Again, assuming that the tires were just cheap and unrealted to the tugging. Could sticky/malfunctioning brakes cause tugging only during acceleration and only at certain rpms/linear pull loads? and what I mean by linear pull loads, it's like at certain amounts physical pulling from the truck is when this happens. It does NOT happen cruising down the road, slowing down or when applying the truck or trailer brakes to stop. Only under acceleration at just the right amount of "pulling force"
I will note that the old tires when filled to 80psi cold, would climb into the mid to high 80's after towing. Even at night with a 70-75 degree ambient temp. And the rubber compound was extremely soft and tread seemed to be melting. Like if you did a sweet burn out in a hot rod and had rubbery residue and string like particles all over your tires. That's how some of the old tires were looking while towing on our last trip and what caused me to buy new tires. I'll try to upload a picture if I can figure it out.
The new tires seemed to only go up to 83psi pulling in the florida heat on our way home during peak sun and 90 degree temps. Also no visible wear after 300 miles.
I was thinking maybe sticking brakes could cause extra friction on the tires causing them to "melt" and blow out. But it could also just be cheap/dangerous tires. Especially since the goodyears appear to not be affected the same way.
