Well the Search function didn't work as it should. Anyway maybe contact angelp for that, but I would think that it would use the default sounds, or the sounds are broken. And a quick look at the Data.ini of the systems, it shows TruckLoop, or TankEngine, which are default sounds, so not sure. If you mean the radar, it intentionally (with a virgin download) shows no sound with the radar vehicle. So what you should do is open that Data.ini and where it says:
[Sound]
EngineSoundName=
MovementSoundName='
Put TruckLoop after the EngineSoundName=
That way you'll have at least a sound with it. But I'm guessing that the sounds are by default anyway, so not sure what I can do to help with that if it's not making sounds while launching.