No reverse in 580 backhoe?

got a 580ck case backhoe with no revers.people try to tell me i got bad reverse clutches. (its a shuttle trans.) it works great win im rolling backwards Little and it will kick right in with no slipping or anything. but, win it does work, i have to have the clutch pedal in.win the pedal is in ,it will work. but win i disengage the pedal it will stop moving. i rebuilt the vale bank thinking that was the problem but it was not. i changed the filter on it to. can anybody with this kind of knowledge give me a honest answer or a suggestion about this? thanks