Just bought it 8 months ago and has 91k about. Only thing I did was have all fluids changed and flushed as well as did complete tune up. Had oem parts all over it so guessing not much was done. Only noticed this issue 2 weeks ago when I was going up our back drive. Then seemed to be at a lower"pulling" speed as it' a steep hill. Then yesterday went up a hill, came to 35 mph and it was growling so I let off and stepped back on the accelerator and all noises were gone. Just wanna make sure it' in goid shape for camping as we pull a 22 ft trailer, Not yet tho we just bought the trailer.