Service intervals, why are they different?

[LD1]

I don't know that this is entirely true. My NH is PTO speed at about 2600 RPM and redline starts at about 3100. My 7.3 turbo diesel in my F250 will do 80MPH at 2500 RPM and redlines about 3500 RPM so, they're pretty close to each other. I don't have a tach on the mini-ex so can't say for certain but, I'd say it sounds like it's about 2500 RPM when it's at operating speed. I've not had any high revving diesel engines, all of mine operate in that 2500 RPM range.

The 7.3 is a much larger diesel engine. Compare it to something that is closer to the same displacement. Like a VW TDI

 

[MORRISONSTEEL]

The NH holds 5ish quarts, the Deere holds a little over 3 quarts, both have a single smallish oil filter.

The hydraulic fluid on the NH (about 8 gallons) is supposed to be changed every 800 hours and on the Deere (a little over 5 gallons), it's recommended to be every 2,000 hours. There are 2 hydraulic filters on the NH, the main and they hydrostatic transmission. The Deere only has one but, it's pretty large.

Hitachi hyd oil is a zinc free oil. Zinc is used in most other hyd oils and is a sacrificial part of that oil, so oils that use zinc as an anti wear additive just don't last as long.

 

[ModMech]

I've got a 40HP NH tractor and a 20ish HP Deere mini-ex. The service interval for oil, etc. on the tractor is 100 hours and on the mini-ex it's 250 hours. Why the difference? Both are small diesels, the mini-ex runs at full throttle most of the time and the tractor runs at varying throttle positions depending on the work it's doing, I'd think that the mini-ex would need the shorter service interval, not the tractor.

Just curious if anyone knows the logic behind this.

Emissions and oil capacity are the two biggest factors.

The larger the sump compared to engine size, the longer the intervals can be.

The more contaminates the oil is subject to (emissions levels), the shorter the intervals should be.