The axel weight doesn't seem right. In 2022 Oliver switched to the D52 (5,200 lb), rated at 3,500 lbs due to the 4-leaf spring. Why would Oliver switch back to 3,500 lbs? I'm not sure you are providing the correct information. The older trailers were 3,500 lbs. and these trailers are experiencing the spring breaking.
5,200 axels have been installed since 2022.