Case 580B will not go into gear without gringing

Just got a 580b a couple weeks ago. I believe it is a 75' model. Diesel engine. It runs well and everything works except the brakes(which do not work at all). It is a shuttle shift. The biggest problem is it will not shift into gear without "really" grinding the gears. I have changed the fluid and filter in the TC and pulled the TC control valve assembly and cleaned it out. Set the power spool to the 3.1" from the center of the closest mount bolt to the center of the cam follower. pushing the "clutch" pedal in causes the pressure to drop out but does not seem to take the pressure off the transmission so it can be shifted into gear. I am hoping some-one in the forum may have experienced this problem in their 580b and can provide some insight which can lead to a fix.---Tx for any help---Randy

Case 580B will not go into gear without gringing