I have the 06, 4.0, I-6, auto Unlimited and have noticed the same thing. Mine has an overdrive off switch. If I am driving around town, I just switch the overdrive off and don't have any problems at all. After driving standards for so long, to me it feels like it shifts into overdrive at too low an rpm. If you use that switch and turn it off in city driving you shouldn't have that problem. Just switch it back on when on the highway or are sustaining high speeds. Might not be the answer that you are looking for, but it works for me.