How do you get a downloaded truck on ETS2
There are two possible problems-
1.A newer version has been released/Game update renders mod incompatible,or,
2.The mod simply doesn't work.
Also, were there any network malfunctions or cutoffs on said network you were on?
My advice is to try refreshing the game a couple of times. If this doesn't work, re-download the Truck from the DLC Browser.