Oil

[Midniteoyl]

As always, use of either type will not void your warranty, so during that time who cares? If, though, you are using the tractor in very cold climates, or very hot, synthetics have shown to have better flow properties under these conditions and their use should be considered.

 

[DeereMann]

The type of synthetic used for engines is polyalphaolefin, fancy chemist talk for long chain hydrocarbon polymers. Same as refined mineral oil except much less variation in length & linkages, and no junk (sulfur, chlorine, wax, etc.). So......why the different impact on elastomeric oil seals? Lubricity....synthetic flows easier, so if you have an incorrectly clamped seal, it will leak faster with synthetic. Simple.

Anyway, for cold temps you want synthetic for quicker pumpability & flow to critical parts on startup & warmup - if you put substantial hours on your engines for longevity. Also in the heat, synthetic does not oxidize (burn/varnish) nearly as quickly - critical for turbocharger bearings.

I use synthetics - change once a year, don't worry about anything. App. 105 hours on new SCUT in 6 mos.