Transmission/Hydraulic fluid for a Buck

[CrashandBurn]

I've been running Universal fluid for quite some time, but now when running the PTO for a long period "log splitter" or "finish mower" I notice a clanking sound from the PTO. Happens only when fluid is hot.
My manual says SAE #80 which I always thought was gear oil, this seems rather thick for the pump and 3 point lift.

who's running what?

 

[alvanko]

Well I don't have a Buck, but I run Universail Hytans oils in my MT372D. JD303 equivalent. (Tractor Supply)

 

[oliver28472]

Yep, that's what I use. If you don't have a loader or other attachments with hydraulics you can go with 80W-90.