My 2009ish Gehl 6640 rather suddenly stopped all hydraulic control to drive motors and lift/bucket as if the safety control switch had tripped or the parking brake was engaged. Happened once while operating aux hydraulic (would only lower the attachment/arms, no drive), cleared quickly, then happened again with bucket only while moving dirt, hydraulics will not engage anymore. Seat and harness switch appear to opperate normal and illuminate/extenguish the parking brake light as it should. what's the next likely culprit? Thanks!
