I have been trying to find out why the trans in my '83 is always shifting too late and noticed my kickdown cable isn't moving, I believe it's extended all the way. I was thinking the modulator was bad but obviously this is the problem.

My question is, should I just drop the pan and see what's going on or is there anything I can do by disconnecting the cable first and looking? I'd prefer not to drop the pan as I just changed the fluid. However, once the pan is off, how hard is it to get to the mechanism? I have no idea why it's hanging up- I did have the carb off and must have messed something up then. It is connected- just not retracting.

 

You could try to 'push it back' - it's mechanical, after all.
When changing the carb, did you pull it hard all the way out?
I've had them hang - up on the side of the case, too.
Sometimes you can pull the cable off the trans at the bottom, and see what's hanging up - just don't loose the connection!
If you can't find it there, pulling the pan might be the only solution.
Use a clean drain pan, and take your time - reuse the fluid.
If I was keeping a car, I found the T-350 pan with a drain plug was worth it!