Goodness. I had the same problems, but mine only howled when I was home...I think...I don't have any neighbors close enough to tell me if he was howling when I was gone.
Do you leave something to occupy him while he's in his crate? Maybe a Kong or something? For me, I just had to put up with it until Gabe eventually stopped. And he STILL will cry/howl on rare occasions. He did this morning, in fact...
I wish I had more encouraging input...
Gable: Black and Red GSD: 03/02/2012 -
Suki: Russian Blue: 03/02/2013 -
Sully: Tri-Color Collie: 04/22/2016 -