Made it 451 miles in our brand new Grand Design Solitude 380FL and noticed it looked crooked and smoke started coming from the drivers side while going 70 mph down I24 in TN. Pulled over and had a torn tire on both sides, axle was coming off due to missing a U bolt and the leaf spring had come apart. Fortunately we were paying attention and caught this as the 16,000 lb trailer would have flipped taking our vehicle and us with it. Mechanic came out, noticed locking bolts were not used on U bolts that were still in place, he was unable to fix it. Grand Design sent a mechanic down the next evening to put the axle back on so we could take it to the dealership. Took to dealership, they were supposed to make it ‘road worthy’ so we could get it to GD Headquarters. This is a new to us vehicle so exactly how it ‘feels’ when towing was also new to us. Noticed part way in the 482 miles to GD that the brakes associated with the previously problematic axle were not working, lots of brake dust on our truck. Once at GD they inspected and fixed multiple issues this caused after quite a bit of fighting with them as they did not want us to bring it to them. They also found we had a major leak in the regulator on our propane tank, mechanics exact words ‘you guys are lucky you didn’t blow up’. Our safety was put in extreme danger multiple times, as was anyone that might have been around us. As said previously, the mechanics at Grand Design did go over the vehicle after fighting with their service manager repeatedly. She wanted to me send pictures and they would deal with it that way. There were no warning lamps or messages. There was smoke 3 days after we purchased this from the dealer brand new.