Could be a couple things. Check your mix program. You may have a switch activated and it's in the wrong position. I use a switch for parking brake on mine, and have it mixed to dn elev.
Could have a hose backwards?
A pic may help.

I just reread your post. I don't know what tx you have, but you need to set your values on the mix the other direction. Or you could try reversing that channel first.
Keep playing with it, you'll get it.