2120 Ford compact tractor occasionally goes into neutral

[90cummins]

I知 doing a service on my friends 2120 HSS which has a couple operational issues.
Occasionally while operating the transmission will go into neutral then re-engage. Transmission is full and oil and filter have been changed.
It has done this for a couple years and does not act like an electrical issue.
Also the hydrostatic steering stops working at times then resumes.
These two systems are totally separate and do not act up at the same time.
Looking for advice.

90cummins

 

[kirkawilson]

FO-46 I&T shop manual says under troubleshooting paragraph 98:
1. Tractor will not move or operates erratically,
a. Engine clutch or transmission input shaft failure,
b. Transmission oil level low,
c. Charge pump or charge pressure relief valve defective,
d. Pump or motor cylinder block or valve plates defective,
e. Feed valve or neutral valve sticking open.