Hey mate,
Nah it is only TDU i thought that myself. And i decided to experement for an hour or so before posting :) I even tried sending all sound via the sound driver settings to the right side to check...all i get is some ambience and barely any engine.
I also set the system sound to mono and still notta. I have a feeling there is a setting in TDU somewhere be it a config file or something to chaneg this...but where it is...i am not sure:)
I did a re-install today and still the same issue. Kinda odd. But again it has been over a year since i last played this game also...maybe the engine, GPS...etc were always at the left. lol
BTW this system is a very high end unit and the sound has been tried through the Nvidia HD audio on my 2 GTX460 cards, my onboard Realtek HD audio as well as a diagnotic card i have laying around. All proved the same results :)
I checked for port conflicts (not always do they cause crashes or the like. but some weird sound issues...i build and repair PC's fora living and was an IT network manager for 5 years ;) )
I dunno. It is a monor annoyance. If it was across the board on all games and apps then i would concede a hardware/system glitch. In this case however, it is not. It is just a TDU glitch :)
EDIT:
Its fixed. I forgot to re-install my megapack and the 1.66a patch lol.