Hey, I got a 2012 Titan with a 6" lift and it has been making a hard grinding noises whenever I press down to accelerate fast from a red light, it also seems to come from the rear. If I accelerate slowly/normal the noise doesn't happen. The grinding sound is really harsh and the truck will vibrate. The grinding happens almost immediately and goes away if I release the pedal or get up to speed. I don't know if its because fast accelerations from a stop are bad for the truck or if there is a more serious problem behind the noise. I was thinking the rear diff but upon research and videos the grinding I'm experiencing seems way to harsh for what I saw on the videos and websites for it to be the diff.