troy,
I have a 5740C that I bought back in 2005. The problem you are having is common and really no big deal. It happens with my tractor about once a year at least. The owners manual states that when shifting gears on your tractor that you should do it slowly and go through the H without speed shifting, in plain words. The fix is simple since all it is is that the gear linkage has gotten hung up. Look in from the passengers side, immediately under your cab and you can look in one of the frames holes and see the linkage hung up. Just use a piece is PVC pipe, a shortened broom handle, or whatever you have and reach into where the linkage is and tape the hung up linkage lightly so it is knocked off the other linkage and falls back to where it belongs, along side the other linkage, Oh and keep the piece of whatever you used to tap the linkage because you.ll be using it again, I promise you!! Great tractor though!!