ToyotaCare 25k / 2 year

I was RE 45 Years ago. Retired now after almost 40 working for an aerospace co, in Seattle.

Synthetics even back then were 3x longer life than conventional oils. I’ve have had good luck with changing conventional oils at 3K and synthetic at 5K and will continue to do so. I believe I read the Tundra that went a million miles had the oil changed at 5 K intervals.

My Tundra has the engine and transmission fluid cooler. My towing is lightweight, but add passes with a 5000+ ft elevation gain, it puts a strain on things.

I’m not familiar with any main bearing failures on the Tundra. I’ll have to look that up.

 

Don't bother with researching main bearing failure, as I've never read of one, at least in this subject. I only cited it as a possibility since you mentioned bearing fatigue of some sort earlier. The million mile Tundra supposedly had 115 oil changes at or around 8700 miles.
His use as a hot shot driver and placing the majority of miles via the highway is remarkable to say the least, especially when his repair list was so small.
It does show a remarkable difference in use compared to the majority of us. Toyota did mention the internals were exceptionally clean and with little wear.
I currently have a 10k/10 month schedule, not the 10k/12 month Toyota suggests. I generally expire on time, and change around 8700-9200 miles on synthetic dealership oil.
I do operate the truck in 30 plus days of 100F. Not Phoenix or death valley.. I am curious about the transmission. I know they mentioned 100k but 60-80k seems more appropriate. Tough call. Do they change hydraulic fluid in aircraft often?

 

We would only change Air Force aircraft hydraulic oil if contamination was suspect at least on the fighters I worked on. If fluid was cloudy, discolored, or a mechanical item had failed that sent metal into the fluid etc. However, the aircraft system had fluid filters with tattle tales that would indicate the filter housing had tripped into bypass. If the pin was popped we would inspect or reset as circumstances/'technical orders would require. In addition, aircraft hydraulic power test ground equipment had large filters that would clean the fluid as the system was operated circulated.

FYI: Jet Engine oil was sampled regularly. Single engine aircraft were sampled after each flight. Sample results would drive maintenance as required. No "scheduled" engine oil changes were done.