580C Mech. Shuttle jumps out of FWD

Hello all. Haven't been on in awhile and probably have posted this issue year or more ago but cant find it. Was wondering if someone could tell me what would cause my shuttle to jump out of fwd as soon as you let clutch out. Reverse is fine. Only thing I have noticed is the linkage underneath that has the 2 ball joint ends are wore out bad. Alot of slop in linkage didn't know if that would cause this or not. Haven't taken the shuttle out of machine yet. Any help would be appreciated.

Thanks,

Bob

580C Mech. Shuttle jumps out of FWD