Starting from version 2.0, RX56 PermVehicles includes native support for tow trucks.
When a player uses a tow truck to move a persistent vehicle, the script automatically tracks the position of the towed vehicle in real-time. If the server restarts, both the tow truck and the vehicle it was carrying will spawn exactly where they were left.
Configuration
In your config.lua, you will find the Config.TowTrucks array:
Adding new trucks: Simply add the spawn name (hash) of any custom add-on tow truck you install on your server to this list. The script will automatically start tracking towed entities for that model.
Trailers: The script also natively supports standard attachable trailers (like those used by the phantom semi-truck). Their positions and mods are saved along with the main cabin.