should i worry about anything if dumb ass mazda put part synthetic in my car today when i asked for full synthetic???
manual says for the rear diff and transfer case:
If the vehicle is operated under any of the following conditions, change the rear differential oil every 45,000km {28,100 miles}
a) Driving in dusty, sandy or wet condition
b) Extended periods of idling or low speed operation
c) Repeated short trips of less than 16 km {10 miles}
If this component has been submerged in water, the oil should be changed.
I take that to mean about every 30k.
Updated the engine oil section with notes on the use of thicker viscosity oils, quantity increase due to balance shaft delete mod and additional oil filters & their part numbers.