I'm trying to find what filter number is required for the transmission on this motor grader so I can track one down. I have a trans issue that I suspect could be resolved with a filter. My local Komatsu dealer parts guy looks like a deer in the headlights on this.
Try Weller Tractor Spares in Kansas. Always had great service from them with regard to Galion/Dresser Parts
I changed the filter, still having an issue. The machine runs well in all gears as well as forward and reverse, but after a half hour or so it will gradually start to not pull / slip but I can stop for a few minutes and it will go again but then will do the same thing over again. Does the same in all gears. If I run it at half throttle it seems to do better. Wonder if the charge pump is the problem, maybe the torque converter. Unfortunately I do not have a manual for this machine.
Plain hyd oil will cause this very thing. Several jobs back we had a T-500C and I always ran type F ATF in it. You may need to check the neutralizer and see if pressure is building in the cylinder and putting the machine in neutral on you.