Smokey Bear

Hello all, I am new to this forum. I have a 2005 3500, 8.1 liter, Allison tranny. I bought this 3 years ago from an old guy with 1595 miles on it. It still smelled new!! Periodically, when I reverse out of my driveway or a parking stall, the engine "lurches". The rpm's rev approximately 4-500. This has been happening for the 3 years I have owned it, it's mostly just inconvenient and embarrassing! Local dealer says that is an inherent problem in these 2005 Chevy's and there's nothing you can do? Is that right? Any fellow lurchers out there?