What happens to modded trucks in my game if I host a COOP session?

[Toxicwire†]

Do they disappear, with no refund. Do I get a refund or do they just not show up for that session?

[Top]

Before you Host a Coop with Mods OFF on a Save you use Mods - It is best to gather all your Mod Trucks on that Save and Sell them first, before you Host. This way you won't lose them. You can always buy them back later.
There is No need to turn them Off, you can just sell them and leave them turned On.

If you Coop as a Guest on your Save with Mods in a Session without Mods - There is no need to sell them or turn them off; you can join any Coop with them still on and you will not lose them on your save. They will still be where you left them when you go back into your save.

[Odysseus]

I host with a coop with mode off , and i just lay my moded truck outside a garage before lunch the multiplayer session , on a map i dont do in multi , and they are just here when i come back to solo . If you lunch your multiplayer session with moded truck inside a garage , the game sell all those truck.