Manual says to chnage hydrofilter at 50 hours.Did that . Change fluid at 100 hrours. Getting close to that time now on a 6 year old splitter(MTD) Sears 27 ton. What say you the experts.
No magnetic plug that I can tell, just a short dip stick from filler top.+ for a filter change only. Does the tank have a magnetic plug? Have a look if it does and see if any filings are collecting on the plug and decide from there.
Holds 3 and half gallons of fluid.
Other factors to consider, how is the equipment used, in what environment, and how has it been stored?
Are you running it hot, and putting away wet? What duty cycle? Humidity will be drawn from outside air, and condense in the warm tank as it cools. Storage is similar in issue. Is it stored indoors or out, protected from weather/humidity?
One option is to pull a uniform sample and have it tested if you have someone locally, or mail in if no one is close. Most testing companies will give results and recommendations based upon their findings.
Here is an interesting article;
http://hydraulicspneumatics.com/200...s/Article/False/6436/TechZone-HydraulicFluids
You've noted that fluid isn't too expensive, thus I would recommend meeting or exceeding the manufacturer's recommendations. You might also consider adding better grade fluid and air filters.
Cheers and good luck.