I ended going to talk to a JD mechanic. the entire dealership went out of their way to help me and answer questions. customer service is top notch.
Bottom line- JD doesn't even try to fix this part, its a $1,200 throw away.
Kanzuki doesn't sell parts to consumers in the U.S.A. Unbelievable since the dealer can buy almost every component of the pump and sell it to me.
I took it home and removed the pump. Now that I had nothing to lose I put it on my transmission table and started disassembling. There are only a couple wearable parts in the whole pump. Its all mechanical. Cleaned everything in the parts washer, checked to make sure all orifices were clear and detente balls moved. Some of the pump plungers were sticking. Very tight tolerances. Couldn't say if they were stuck before or after disassembly. An hour later I reassembled the pump and re-installed it. That took longer than anything else. Pump works fine now.
Best guess- there was an air bubble somewhere in the (R) side of the system that wouldn't purge.