When I shift gears manually I've noticed the trans have a delay before it shifts to the next gear. what would cause this? Valve body problem?

 

Here is a little insight on how this works. W/O you realizing it, the same thing happens when you let it auto shift, perhaps even more so. Now a couple of things can be going on. One is that the point that you select to move may be before the auto upshift point and thus that takes over (you did not say this was anything but an auto shift and not a manual shift). Next, it takes a certain amount of time from when the shift valve moves to when the shift actually completes and that has to do with both calibration and clutch/band quality. With a tranny in "good" condition and a TransGo Reprogramming Kit you should have she shift occur much more quickly but again if you have an engine that let's say would be better off shifting at 5000 RPM and it is calibrated to shift at 5500 RPM WOT you would need to address that via Governor recalibration fo optimum performance and to keep that delay from occuring. I hope this helps.