[hatzie]

Originally Posted by jocko

Thx Hatzie, appreciate the input. I may go with the following based on what I've seen so far:
- spin-on (only, without pan drain) every 12.5K
- spin-on (with pan drain) every 25K
- spin-on, pan drain, and internal trans filter every 50K per the manual

With the 25K service, I'll check the fluid to see how it looks, and maybe skip this in the future, it is still likely overkill.

Thanks again!

Sounds like a plan. That's mostly what preventive maintenance is.
Changing the fluids is cheaper than overhauls.

I read an article back in the late 1980's where they did an actual real world test on a handful of NYC taxi cabs. 3K, 5K, 7.5K, & 10K oil changes for 100K miles IIRC but it might've been 200K. They did lab tests on the oil. The wear metals had started to rise slightly toward the end in the 7.5K and 10K groups but the engine teardowns showed insignificant cylinder, piston, and bearing wear after 100,000 miles for all four groups.
I use the 5K and 5K multiple intervals because they're easy to remember and seem to be soon enough.