I purchased a 1980's Case 680G backhoe from a neighbor. He told me he was driving it and it suddenly stopped moving forward. It would shuttle into reverse and move, but not forward. There wasn't any metal in the fluid when he drained it and he filled it with new case fluid. I am an automobile technician by trade, but no clue where to start on this shuttle unit. Pulled the valve body hoping I'd see something obvious, but I'm not sure if the valves are even moving like they should (seem difficult to move). Any suggestions?
Well, worked on it some more. Couldn't find anything that would indicate a valve body problem. The fluid flow charts from the service manual are pretty straight forward, going to have to put the valve body back on and do a pressure test. It has to be either a failed seal on the forward side or splattered disks. Will have to remove it in all likely hood either way.
I wonder if yours is related to my old 480C shuttle? Keep us updated, maybe some pictures. Mine is a little sluggish in forward, and the couple of things I found on it suggest the clutch discs are burnt up in forward.