Ok, I've been having an issue for the last week. I have a 700R4 auto and it shifts fine in any gear other than 2nd. If I drive with overdrive enabled the revs climb in first well past the regular shift point and then the revs fall to where third gear should be. It doesnt slip, but completely skips 2nd. If I manually step through the gears, 1st and drive are fine but in 2nd it just races, like the transmission is in neutral. So, basically no second gear. No slippage in other gears through. I pulled the pan and found a small screw that had been caught by the pan debris magnet, but other than that the fluid looked great. Could this be a valve body or control problem? Or a broken band? I'm hoping it's some sort of control issue and not something where it needs to be torn into.

Sounds like the 2-4 band took a crap. You might just be lucky, and it's just that the servo's apply pin doesn't engage the band completely- but that's a wild chance.

Note that when you row your own (shift manually), when the stick's in 1st or 2nd gear position, the line pressure (internal trans fluid pressure) is almost DOUBLE the normal presure. So that might "mask" a problem. For instance, my trans will slip in 2nd (under light throttle) and 4th (medium throttle upshift) But if I row my own, the trans hits 2nd - and most importantly, it stays in 2nd and doesn't slip out.

without 2nd gear you have the possibility of overspeeding the engine on a kickdown.for example if the road speed and throttle position call for a 4/2 or a 3/2 kickdown the valve body will exhaust the 3/4 clutch pack and back pressure on the servo allowing it to re apply.with a non functioning band the transmission will go back to first gear.this can cause engine overspeeding and result in engine damage.