1975 International Loader/Backhoe 3500A - Stopped Going Forward

[jmsjolly]

While running loads of item 4 out of the driveway with a lot of forward, reverse, forward, reverse work, the forward stopped working. I had to push the unit out of the driveway with the boom. It will just not engage in forward and I have no idea why. Any ideas? I did just blow and replace a hose - perhaps I got an air bubble? Don't laugh too hard, I am a newbie with the backhoe. I was feeling good until this happened - though I am proud of myself for walking it out of the driveway. Any help?!?!