JD 4850 8 speed PWRshift problems

I have a 4850 powershift with the old 8 speed trans. Earlier in the summer, the hydraulic system started starving and upon pulling filters and screen, found the old woven style brake linings were shedding out and plugging the system. Cleaned the screen and new filters and back in the field maybe long enough to finish the summer. No luck. System starved out again, but this time, the filters were plugged with antisieze looking goop in the filters. Likely brake disc(s) being ground up. The problem which now has arisen and is much more serious is the transmission it loading down in most of the speeds. Does anyone here have experience with these transmissions? In reverse; 1 and 2 work, 3 and 4 lock down. Forward; 1 and 2 work, 3,4,5 and 6 lock down while 7 and 8 are still working. All the nonworking speeds have C2 clutch in common. I am hoping the control valves are getting stuck from the metal particles in the system as it was working fine before the linings let loose and it hasn't been under heavy load since.

JD 4850 8 speed PWRshift problems