heres some sounds i just made and i gota say they sound great they are from a 400 Big Cam cummins cridit for these sounds go to Hodrodx199 for the sounds and me for putting them into RoR
installation:
for .36.1 users add the files that say default_diesel in front of them into Rigs of Rods 0.36.1/resources/sounds.zip
for .35 users add the files named iddle, low, high, force, and medium to 0.35/data/sounds/engine