Originally Posted by Jim34RL
What legal law are you referring to? In IL all you have to do is licenses the truck for the gross weight you want to pull if you are commercial. My sons 3/4 Ram truck is licenses with D plate that has a gross weight of 30,000 lbs. This is to allow him to pull his car trailer with any vehicle on the trailer. DOT only looks at tire carrying ability and the license plate load registration of commercial vehicles.
FYI... a D plate in Illinois is only good for up to 12,000 lbs. Truck plate only accounts for the weight on the truck axles only. If, some how, your son has 30,000 lbs on the axles of a 3/4 ton he would need a K plate (28001-32000).
In Illinois, the flat weight plates should be bases on the GVWR Of the truck. He has D plates, as that 3/4 ton should have a GVWR of 9000 lbs, which fits nicely in the 8,001 to 12,000 lb range for a D plate.
If your son is legally (by plates) at 30k gross, then he would also need a TK plate on that trailer...