When starting from a dead stop, my new TCH begins in silent/smooth battery mode, but almost immediately I experience a faint rumble, akin to going over a set of small washboard bumps or a cattle guard. I've duplicated this over and over in every attempt to repeat it, BUT it only happens immediately prior to the gas engine kicking in. If I am careful to keep it at a crawl, utilizying the battery alone, this does not happen, and then when accelerating from this crawl it also does not occur when the gas engine kicks in. It is so subtle, that my wife had to point it out to me, but now I am sensitive to it as well. I would be real curious to find out if anyone else is experiencing this.