Reverb not working on recorded tracks

I have a problem. I am trying to add reverb to some audio tracks that I recorded directly into Garageband. I move the slider around and there is no change in the reverb on the track. Also when I am listening to the song and I click on a new vocal present that has reverb built-in then for second or two garageband plays it appropriately with reverb, but within a second or two there is a small click and the reverb is gone. All the other preset effects still work, but the reverb drops out. I can not find anyone else who has had this same problem. I have tried reinstalling Garageband, but it did not work.
Thanks for any help anyone can offer.