I have been noticing lately that my automatic transmission has been hesitant to shift into the next gear on acceleration. I notice a bit of lag from 2nd to 3rd, but then really feel the lag from 3rd to overdrive. I flushed the transmission fluid about a month ago, and refilled with mobil 1 "dino" ATF. Before the flush, I didn't notice any transmission issues, and hadn't noticed anything unusual after the flush until about a week ago. The shifts are not real hard or otherwise jerky. There is just a lag at the higher RPM before it will drop into gear. If I lift a bit on the accelerator when the transmission seems to want to shift to overdrive, then this lifting helps it to engage the overdrive (4th gear). I am wondering where I should look to fix the problem. Is this a possible case of just needing a kickdown cable adjustment, or is it something bigger like the OD solenoid or worn valve ball in the transmission valve body? Any help would be greatly appreciated.