First off - I don't believe in extended drain intervals for an oil simply because it's synthetic. It's true that oil itself never wears out but is simply diluted or contaminated from combustion byproducts as well as just general wear and soughing of materials from the mechanical assemblies.

That said - The TCH is a different sort of animal from your typical ICE propelled vehicle. The ICE runs more at a steady-state or not at all rather than varying RPMs and dynamic loads.

In a normal vehicle, I change my oil every 2500-3000 miles (yes even synthetics which I use in all my vehicles - Mobil-1) - but in the TCH, I think that drain intervals beyond that 3000 mile limit would not be uncalled for.
I would say that 5000 miles would be a reasonable maximum interval.

Mobil-1 0w20 - Minneapolis MN

Regards - Randy




If there's one thing I've learned in online forums its this:
Never argue with an idiot, they'll drag you down to their level and beat you with experience!