JD 410C Backhoe Trans issues - Need advice please

I just had it outside this winter with periodic moving but now something is not engaging in the trans. Got it working OK but I have a hesitation when going from reverse to forward etc when shifting reverser lever on dash on operation. It seems when it warms up for 10-15 minutes the shaft from the engine to trans spins at full speed and then the clutch engages, but still very stiff unless I use it for a while few days. I lubed the linkage, but it seems to be in the clutch engaging mechanism or reverser?? The clutch pedal that is satiff links to a hydraulic cylinder, I believe similar to a slave cylinder.

Any clue where to start or obvious problem. I will change the reverser and main hydraulic filters, fluid and torque converter fluids next week - and unknown when done last - just need to know if there seems to be an obvious bigger problem here? Could it be a bad "slave" or possibly bad torque converter or worn out clutch plates? I am not sure if these are pressure plates or hydraulic pressure type of engaging??? Anyone know anything about this? I am worried big buck repairs lie ahead!

THANKS for any help!