I have a new 2021 Promaster 3500 Roadtrek RV with 4000 miles on it that came from the factory out of line. It pulls to the left and is wearing down the inside of both front tires. It is in for the 3rd line up under warranty. It runs down the road fine for about 50 miles then starts pulling to the left again. The dealer is blaming the problem on the fact that it has been made into an RV. I know this can't be so because there are thousands of Promaster RV campers on the road most are running correctly. I am sure that Thor, Winnebago and Roadtrek would not use the Promaster as their most built class B campers if they were not capable of handling the job. Has anyone heard of this problem?