This may be normal. With overdrive disabled my truck does not seem to hold the RPM in stop and go traffic. This would be that annoying parking lot stuff. At about 30mph it seems to hunt a little, like it may be shifting up to quickly. When overdrive is enabled it seems to work perfect running up the rpm before shifting, and downshifting at the proper points. Is there some difference that I am unaware of between OD on, and OD off...driving in city traffic. Now I only deenergize OD when below 55mph with lockup. Can someone enlighten me on this?

 

I've driven my truck with OD off under 55 since day one. I've never experienced any problems like that though.