Hi all. Long time listener, first time caller. I can usually look through the forums and find my answer, but I can't find this one anywhere.
I'm looking at getting an old Bobcat 600 (1970-ish) that has been upgraded with the VH4D engine, so it's effectively a model 610. One of my first jobs will be a fluid change, but I'm not exactly sure what fluid to use. The manuals for this machine specified various fluids over the years, but the design of the machine didn't change (and any design changes could or should have carried over to older machines through replacement parts) The manuals, depending on the revision, either say "an approved oil" or specify 10W-30, 10W-40, ATF (non-specific formula) or in the latest revision I can find, "Black Gold" which seems to be an obsolete Bobcat house brand. So, effectively, it seems like they'll function on pretty much anything, and people are successfully running all of the above.
What would you suggest for the application? Preferably something readily available and not obscenely expensive (I'd rather not buy 20 gallons of Royal Purple at $60/gallon).
This is a clutch machine, not hydrostatic, so the single reservoir serves as hydraulic fluid (~3,000 psi system), chain case lube, and wet clutch lube. It serves everything on the machine except the engine. My main concern is finding a fluid that will give me smooth operation and good clutch life. Since these clutches are used to steer and operate the machine, I'd classify them as medium speed, medium load, medium temperature, but very high slip. What should I be looking for in that respect? Even the premium hydraulic fluids make no mention of wet clutch applications. Would universal tractor fluid be a good choice? It mentions PTO clutches and wet brakes.
I may be overthinking this, but I figured I'd ask before I go buy 20 gallons of whatever.