Ok, I know this is a very old thread. Didn't want to leave this thread unsolved. But I finally got around in fixing this issue. I had another 19' lift where the steer cylinder was leaking fluid from the seals. So I took the steer cylinder from the one that wouldn't drive and steer at the same time and swap it. It still wouldn't drive and steer so I now narrowed it down to problem with the cylinder. I took it apart, the rod was slightly bent. Replaced the rod and all is good.