Sunstrand series 15 type "U"
(Now Sauer/Danfoss)
http://files.danfoss.com/documents/s...l/bln-9646.pdf
Change the oil and filter, it will be fine
Hytran is good but any hyd fluid that meets the specks will do fine.
Do not use 303 hyd fluid as it will not flow at colder temps.
oil requirments on page 12 of manual link
TSC makes a good substitute oil.